A residual voltage measuring device for medical equipment

Abstract

The present invention relates to the technical field of medical safety measuring instruments, and specifically discloses a residual voltage measuring device for medical equipment, comprising: a control module, a relay module, a data acquisition module and a display device; the control module sends a control instruction to the relay module, and sends an acquisition instruction to the data acquisition module; the relay module switches to a test state according to the control instruction; the data acquisition module acquires a test voltage waveform according to the acquisition instruction, and sends it to the control module; the control module determines the positions of the peak and the trough according to the initial phase of the test voltage waveform, generates a start-stop instruction and a re-acquisition instruction according to the positions of the peak and the trough, so as to control the designated relay to be disconnected according to the start-stop instruction, and controls the data acquisition module to re-acquire the test voltage waveform according to the re-acquisition instruction; and the control module tests the re-acquired test voltage waveform to generate and display a test result; the display device is used to output and display the test result.

Description

Technical Field

[0001] The present invention relates to the technical field of medical safety measuring instruments, and in particular to a residual voltage measuring device for medical equipment. Background Art

[0002] GB 9706.1-2020 is the general requirements for basic safety and essential performance of medical electrical equipment of the Chinese national standard. This standard applies to the design, manufacture, installation and maintenance of all medical electrical equipment to ensure that their safety and performance comply with national standards. The standard aims to ensure the safety and reliability of medical electrical equipment during use and protect the safety of patients and medical staff.

[0003] Residual voltage is the residual voltage that remains between the poles of the power plug, between the poles and the device casing, and on easily accessible energy storage devices inside the electrical equipment for a period of time after the electrical equipment is powered off. Excessive residual voltage can cause electric shock, safety accidents, and even casualties.

[0004] GB 9706.1-2020 "Medical Electrical Equipment Part 1: General Requirements for Safety" stipulates: "The ME equipment parts intended to be connected to the power supply through a plug should be designed so that the voltage between the pins of the plug and between each power pin and the shell does not exceed 60V 1s after the plug is disconnected, or if the voltage value is exceeded, the stored charge does not exceed 45μC. The ME equipment operates at the rated voltage or the upper limit of the rated voltage. Disconnect the ME equipment from the power supply when any relevant switch is in the "on" and "off" positions. The ME equipment can be disconnected from the power supply through the plug. In this case, multiple measurements should be made as needed to measure the worst case, or a trigger circuit should be used to ensure that the disconnection occurs at the peak of the power supply voltage waveform. Measure the voltage between the pins of the plug and between any pin and the shell 1s after the power is disconnected with a meter whose internal resistance does not significantly affect the measured value. Note: An oscilloscope and a probe with an input impedance consisting of a resistor of 100MΩ±5MΩ in parallel with an input capacitor of 25pF or less are considered to be an example of an acceptable measurement arrangement. The stored charge can be measured or calculated by any convenient method."

[0005] At present, when conducting residual discharge tests on electrical appliances, most of the test systems are composed of multiple devices such as oscilloscopes, oscilloscope probes, and sockets with switches. Two or even more people operate the equipment power supply and oscilloscope at the same time, which consumes a lot of manpower, has many test uncertainties, and the test process is complicated. The success rate of capturing a single valid waveform is low. Since the power circuit is disconnected randomly, it takes about 10 repeated operations to disconnect the power supply at the peak / trough position, and the test efficiency is low. In addition, since the human eye is used for judgment, the actual disconnection position is not accurate, resulting in a low actual voltage when the power supply is disconnected, making the test results inaccurate and prone to misjudgment, judging the unqualified equipment under test as qualified. These products have certain safety hazards during use, and even safety accidents may occur, causing casualties.

[0006] In addition, since the residual voltage test simulates an open circuit state, theoretically, the greater the internal resistance of the test system, the more accurate the test results. However, the system is actually a closed-loop circuit with an impedance of 100MΩ, so there is a certain error in the test results of the system, which may also cause misjudgment and create safety hazards. In addition, the oscilloscope probe will also introduce certain power frequency interference, affecting the test results. Summary of the invention

[0007] In view of the above problems, an object of the present invention is to provide a residual voltage measuring device for medical equipment, which is used to measure the residual voltage of a plug of a medical electrical equipment.

[0008] The present invention provides a residual voltage measuring device for medical equipment, comprising: a control module, a relay module, a data acquisition module and a display device; the relay module comprises a plurality of relays;

[0009] The control module sends a control instruction to the relay module and sends a collection instruction to the data collection module;

[0010] The relay module is switched to a test state according to the control instruction; in the test state, the three poles of the plug of the device under test and the shell of the device under test are respectively connected to the relay module, the power supply and the data acquisition module;

[0011] The data acquisition module acquires the test voltage waveform according to the acquisition instruction and sends it to the control module;

[0012] The control module determines the positions of the peak and the trough according to the initial phase of the test voltage waveform, generates a start-stop instruction and a re-collection instruction according to the positions of the peak and the trough, controls the designated relay to be disconnected according to the start-stop instruction, and controls the data collection module to re-collect the test voltage waveform according to the re-collection instruction; and the control module tests the re-collected test voltage waveform to generate a display test result, and sends the display test result to the display device;

[0013] The display device is used to output the display test result.

[0014] In a possible implementation, the control module controls the opening and closing of a specified relay in the relay module so that any combination of the three poles of the plug of the device under test and the housing of the device under test is tested on a single test channel, or all test channels are tested simultaneously.

[0015] In one possible implementation, the control module controls the opening and closing of a specified relay in the relay module so that when the power supply is disconnected, the connection between the data acquisition module and the three poles of the plug of the device under test and the housing of the device under test is disconnected at the same time, thereby realizing an open circuit test.

[0016] In a possible implementation, the input resistance of the data acquisition module is greater than or equal to 100 MΩ;

[0017] The data acquisition module has at least three acquisition channels;

[0018] The voltage acquisition range of the data acquisition module includes at least -400V~400V;

[0019] The sampling frequency of the data acquisition module is greater than or equal to 1kHz;

[0020] The continuous sampling time of the data acquisition module is greater than or equal to 2 seconds.

[0021] In a possible implementation, the relay module includes at least 11 relays.

[0022] In a possible implementation, the L terminal of the power plug of the device under test is connected to the common terminal of the first relay and the normally closed terminal of the fourth relay at the same time;

[0023] The N terminal of the power plug of the device under test is simultaneously connected to the common terminal of the second relay and the normally closed terminal of the sixth relay;

[0024] The ground terminal of the power plug of the device under test is simultaneously connected to the common terminal of the third relay, the normally open terminal of the fifth relay, the normally open terminal of the sixth relay, and the normally closed terminal of the tenth relay;

[0025] The housing of the device under test is simultaneously connected to the normally open terminal of the 7th relay and the normally closed terminal of the 11th relay.

[0026] In a possible implementation, the L terminal of the power supply is connected to the normally closed terminal of the first relay;

[0027] The N terminal of the power supply is connected to the normally closed terminal of the second relay;

[0028] The ground terminal of the power supply is connected to the normally closed terminal of the third relay.

[0029] In a possible implementation, the positive terminal of the CH0 channel of the data acquisition module is connected to the common terminal of the 8th relay;

[0030] The positive terminal of the CH1 channel of the data acquisition module is connected to the common terminal of the 10th relay;

[0031] The positive terminal of the CH2 channel of the data acquisition module is connected to the common terminal of the 11th relay;

[0032] The negative terminal of the CH0 channel, the negative terminal of the CH1 channel, and the negative terminal of the CH2 channel of the data acquisition module are simultaneously connected to the common terminal of the ninth relay.

[0033] In a possible implementation, the common terminal of the 4th relay is connected to the normally closed terminal of the 5th relay;

[0034] The common terminal of the 5th relay is connected to the normally closed terminal of the 8th relay;

[0035] The common terminal of the 6th relay is connected to the normally closed terminal of the 7th relay;

[0036] The common terminal of the 7th relay is connected to the normally closed terminal of the 9th relay;

[0037] The normally open terminals of the 1st relay, the 2nd relay, the 3rd relay, the 8th relay, the 9th relay, the 10th relay and the 11th relay are suspended.

[0038] In a possible implementation, the first relay, the second relay, and the third relay are used to control the on and off of the power supply;

[0039] The 8th relay, the 9th relay, the 10th relay and the 11th relay are used to control the on and off of the CH0 channel, the CH1 channel and the CH2 channel of the data acquisition module respectively;

[0040] The 4th relay, the 5th relay, the 6th relay and the 7th relay are respectively used to control and select different test channels.

[0041] The residual voltage measuring device for medical equipment provided by the present invention has the following beneficial effects:

[0042] 1) It can realize automatic disconnection at the peak / trough of the power supply waveform without repeating the operation about 10 times. The test efficiency is high, which greatly saves manpower and time, and has higher test accuracy;

[0043] 2) The residual voltage of the tested port can be tested by triggering the relay through the voltage wave of other ports, which is powerful;

[0044] 3) It can automatically generate the test waveform and calculate the voltage value 1 second (or n seconds) after the power supply is disconnected, with high test efficiency;

[0045] 4) It can realize simultaneous testing of all test channels in any combination of the L, N and ground three-pole of the device under test plug and the four terminals of the device under test shell, with high testing efficiency;

[0046] 5) The relay connection method adopted can effectively avoid the short circuit between the L (live wire) of the power supply and other terminals, ensuring the safety of the test;

[0047] 6) It can realize true open circuit test, and the test results are more accurate;

[0048] 7) It can realize self-calibration to ensure the accuracy of test results;

[0049] 8) Support the test mode of testing and correcting at the same time;

[0050] 9) The voltage acquisition has high accuracy, the waveform distortion is small, and the test results are more accurate;

[0051] 10) It has strong anti-power frequency interference capability, the test waveform is more realistic and the test result is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 A schematic diagram of the structure of a residual voltage measuring device provided by an embodiment of the present invention;

[0053] Figure 2 A connection diagram of a relay module provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0054] The following detailed description of the embodiments of the present invention is further described in detail in conjunction with the accompanying drawings and examples. The detailed description of the following embodiments and the accompanying drawings are used to exemplarily illustrate the principles of the present invention, but cannot be used to limit the scope of the present invention, that is, the present invention is not limited to the preferred embodiments described, and the scope of the present invention is defined by the claims.

[0055] In the description of the present invention, it should be noted that, unless otherwise specified, “plurality” means two or more than two; the terms “first”, “second”, etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance; for ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0056] Figure 1 A schematic diagram of the structure of a residual voltage measuring device provided by an embodiment of the present invention is shown in FIG. Figure 1 As shown, the present invention provides a residual voltage measuring device for medical equipment, comprising: a control module, a relay module, a data acquisition module and a display device; the relay module comprises a plurality of relays;

[0057] The test software is directly installed in the control module. The control module is connected to the display device through the LVDS video cable and the USB cable. The L, N, and ground of the EUT power supply are directly connected to the designated port of the relay module. The designated port of the relay is connected to the L, N, and ground of the EUT power plug and the shell, and is connected to the designated port of the data acquisition module. The relay module and the data acquisition module are connected to the control module through the RS232 interface and the USB interface respectively.

[0058] The control module sends control instructions to the relay module and sends collection instructions to the data collection module;

[0059] The relay module switches to the test state according to the control instruction; in the test state, the three poles of the plug of the device under test and the shell of the device under test are respectively connected to the relay module, the power supply and the data acquisition module;

[0060] The data acquisition module acquires the test voltage waveform according to the acquisition instruction and sends it to the control module;

[0061] The control module determines the positions of the peaks and troughs according to the initial phase of the test voltage waveform, generates a start-stop instruction and a re-collection instruction according to the positions of the peaks and troughs, controls the designated relay to be disconnected according to the start-stop instruction, and controls the data collection module to re-collect the test voltage waveform according to the re-collection instruction; and the control module tests the re-collected test voltage waveform to generate a display test result, and sends the display test result to the display device;

[0062] The display device is used to output and display the test results.

[0063] In a possible implementation, the control module controls the opening and closing of a specified relay in the relay module so that any combination of the three poles of the plug of the device under test and the housing of the device under test is tested for a single test channel, or all test channels are tested simultaneously.

[0064] The control module can also control the opening and closing of a specified relay in the relay module so that when the power supply is disconnected, the connection between the data acquisition module and the three-pole plug of the device under test and the housing of the device under test is disconnected to achieve an open circuit test.

[0065] The test software first sends instructions to the relay module through the control module to realize the connection status of the L, N, and ground three-pole of the plug of the device under test and the shell of the device under test with the relay, power supply, and CH0, CH1, and CH2 three channels of the data acquisition module to realize the test state of the test experiment;

[0066] Then control the relay module to work, so that the L, N and ground of the device under test plug are connected to the corresponding ends of the power supply, so as to realize the capacitor charging of the device under test. The L, N and ground of the device under test are connected to the corresponding channels of the data acquisition module at the same time.

[0067] Then, the control module sends instructions to the data acquisition module to collect the voltage waveform. By testing the initial phase of the voltage waveform, the time difference △t between the initial time and the peak / trough position is calculated, so as to find the peak / trough position of the voltage waveform. At this position, the specified relay is triggered to disconnect, so as to disconnect the power supply voltage at the peak / trough position and collect the waveform.

[0068] Finally, the waveform is tested to obtain the voltage value after 1 second (or n seconds), and it is determined whether it meets the standard requirements. If it does not meet the requirements, an alarm is issued.

[0069] In a possible implementation, the input resistance of the data acquisition module is greater than or equal to 100MΩ; the data acquisition module has at least 3 acquisition channels; the voltage acquisition range of the data acquisition module includes at least -400V~400V; the sampling frequency of the data acquisition module is greater than or equal to 1kHz; and the continuous sampling time of the data acquisition module is greater than or equal to 2 seconds.

[0070] The data acquisition card is connected to the control module through a USB interface or other communication interface. The control module sends control instructions to the data acquisition module, configures the data acquisition module, and controls the data acquisition module to start / stop acquisition. The data acquisition module sends the collected data to the control module for the test software to call. The data acquisition module needs to be powered independently. For example, the relay module can use a 4115B 4-channel data acquisition module, or other data acquisition modules with complex requirements can be selected.

[0071] In a possible implementation, the relay module includes at least 11 relays, which are connected to the control module via an RS232 interface. The switching of channels and the on / off of the test circuit are realized by opening and closing the 11 relays in the relay module. The relay module needs to be powered independently. The relay module can adopt the YK-16 RS232 / RS485 relay module, or other relay modules that meet the requirements.

[0072] Figure 2 A connection diagram of a relay module provided in an embodiment of the present invention is shown in FIG. Figure 2 As shown, the relay module and the data acquisition module are both powered by 12V DC. The L terminal of the power plug of the device under test is connected to the common terminal of the first relay and the normally closed terminal of the fourth relay at the same time;

[0073] The N terminal of the power plug of the device under test is connected to the common terminal of the second relay and the normally closed terminal of the sixth relay at the same time;

[0074] The ground terminal of the power plug of the device under test is simultaneously connected to the common terminal of the 3rd relay, the normally open terminal of the 5th relay, the normally open terminal of the 6th relay, and the normally closed terminal of the 10th relay;

[0075] The housing of the device under test is connected to the normally open terminal of the 7th relay and the normally closed terminal of the 11th relay at the same time;

[0076] The L terminal of the power supply is connected to the normally closed terminal of the first relay;

[0077] The N terminal of the power supply is connected to the normally closed terminal of the second relay;

[0078] The ground terminal of the power supply is connected to the normally closed terminal of the third relay;

[0079] The positive terminal of the CH0 channel of the data acquisition module is connected to the common terminal of the 8th relay;

[0080] The positive terminal of the CH1 channel of the data acquisition module is connected to the common terminal of the 10th relay;

[0081] The positive terminal of the CH2 channel of the data acquisition module is connected to the common terminal of the 11th relay;

[0082] The negative terminal of the CH0 channel, the negative terminal of the CH1 channel, and the negative terminal of the CH2 channel of the data acquisition module are simultaneously connected to the common terminal of the 9th relay;

[0083] The common terminal of the 4th relay is connected to the normally closed terminal of the 5th relay;

[0084] The common terminal of the 5th relay is connected to the normally closed terminal of the 8th relay;

[0085] The common terminal of the 6th relay is connected to the normally closed terminal of the 7th relay;

[0086] The common terminal of the 7th relay is connected to the normally closed terminal of the 9th relay;

[0087] The normally open terminals of the 1st relay, the 2nd relay, the 3rd relay, the 8th relay, the 9th relay, the 10th relay and the 11th relay are suspended.

[0088] All terminals of the CH3 channel of the data acquisition module are suspended; all terminals of the 12th to 16th relays are suspended.

[0089] The on / off of the test circuit and the selection of the test mode and test port are mainly realized by the relay module. The specific implementation method is as follows:

[0090] The 1st, 2nd and 3rd relays serve as the on-off switches of the power supply and are responsible for disconnecting and closing the power supply. When the 1st, 2nd and 3rd relays are in the ON state, the power supply is disconnected, and when they are in the OFF state, the power supply is disconnected and closed.

[0091] The 8th, 9th, 10th and 11th relays serve as the on-off switches of the CH0~CH2 channels of the data acquisition module. The 8th, 10th and 11th relays are the positive terminal on-off switches of the CH0~CH2 channels of the data acquisition module, and the 9th relay is the negative terminal on-off switch of the CH0~CH2 channels of the data acquisition module. When the 8th, 9th, 10th and 11th relays are ON, the corresponding terminals of the data acquisition module are disconnected, and closed when OFF. When all are ON, the data acquisition module is disconnected.

[0092] The 4th, 5th, 6th and 7th relays are used as selection switches for the test channels, and the 10th and 11th relays can be used to select the test ports. The present invention can realize the simultaneous test mode of L (live) - N (zero) - E (ground) - W (shell), and the separate test modes of LN, LE, LW, NE, NW and EW. In the LNEW simultaneous test mode, the CH0, CH1 and CH2 channels of the data acquisition module respectively collect the voltage waveform data of the LN, EN and WN terminals. In the separate test mode, the CH0 channel of the data acquisition module collects the voltage waveform data of the corresponding port, and the CH1 and CH2 channels do not work.

[0093] The test mode and test port switching are implemented as follows:

[0094] LNEW: 4th, 5th, 6th, 7th relays: OFF, 10th, 11th relays: OFF;

[0095] LN: 4th, 5th, 6th, 7th relays: OFF, 10th, 11th relays: ON;

[0096] LE: 4th, 5th, 7th relays: OFF, 6th, 10th, 11th relays: ON;

[0097] LW: 4th, 5th, 6th relays: OFF, 7th, 10th, 11th relays: ON;

[0098] NE: Relays 5 and 7: OFF, relays 4, 6, 10, and 11: ON;

[0099] NW: Relays 5 and 6: OFF, relays 4, 7, 10, and 11: ON;

[0100] EW: Relays 4 and 6: OFF, relays 5, 7, 10, and 11: ON.

[0101] The advantage of configuring the relay in this way is that even if the relay module fails, it will not cause the L (live wire) to short-circuit with other terminals, thus avoiding safety accidents.

[0102] The function of automatically disconnecting the power supply at the peak / trough position of the voltage waveform is realized by the data acquisition module, the relay module, and the test software. The following takes the peak position as an example to outline the implementation process of automatically disconnecting the power supply at the peak / trough position of the voltage waveform.

[0103] The test software sends corresponding instructions to the relay module through the RS232 serial port according to the communication protocol provided by the relay module, and selects the corresponding test port. Here we take the LN port as an example:

[0104] Set the status of relays 4, 5, 6, and 7 to OFF, and the status of relays 10 and 11 to ON to implement the LN interface test mode; set the status of relays 1, 2, and 3 to OFF to close the power supply to the EUT; set the status of relays 8 and 9 to OFF to close the CH0 channel of the data acquisition module.

[0105] The test software configures the data acquisition module according to the driver provided by the data acquisition module, sets the sampling rate to 10kSa / s, starts acquisition, reads the voltage waveform of about 0.1s, calls the "Extract Single Frequency Information" function in LabVIEW, measures the frequency and phase of the voltage waveform, and calculates the time difference △t from the start time of the waveform to the peak position through the phase and frequency. 1 .

[0106] In order to compensate for the response time of the relay, program running time and other factors, the adjustment time △t is introduced here 2 , call the "high-precision polling wait" function in LabVIEW to achieve accurate delay, and set the delay time to △t 2- △t 1 Then use the RS232 serial port to send instructions to the relay module, set the status of the 1st, 2nd, and 3rd relays to ON, and the status of the other relays remains unchanged. Disconnect the power supply and realize automatic disconnection of the power supply at the peak / trough position of the voltage waveform.

[0107] Adjustment time △t 2 It can be set manually through experimental data, automatically through a correction program, or in real time through a test-while-correction mode.

[0108] The method of automatically disconnecting the power supply at the trough position of the voltage waveform is basically the same as the method of automatically disconnecting the power supply at the peak position of the voltage waveform. It only needs to reduce the delay time from △t 2- △t 1 Change to △t 2- △t 1 +T / 2, T is the period of the power supply voltage waveform.

[0109] During the test, the voltage wave of other ports can also be used to trigger the relay to test the residual voltage of the test port. First, the trigger port is connected to the corresponding port of the data acquisition module by using the relay, and the voltage waveform of the trigger port is collected. After calculation, the power supply is disconnected by using the relay, and the test port is switched to the data acquisition module by using the relay to collect and calculate the test waveform.

[0110] In order to make the test waveform show the entire trend of voltage attenuation after the power supply circuit is disconnected, it is necessary to control the data acquisition module to start collecting data about 0.1s before sending the power supply disconnection instruction to the relay module, call the "Create Waveform" function in LabVIEW to generate the test waveform, and call the "Waveform Graph" control in LabVIEW to display the test waveform.

[0111] In order to determine the circuit disconnection position in the test waveform, the correction time △t is introduced here. 3 , the circuit disconnection position in the test waveform is △t 2- △t 1+ △t 3 △t 3 It is relatively stable and can be manually set by observing the test waveform through multiple tests. To facilitate the test, set the X scale offset of the waveform to -(△t 2- △t 1+ △t 3), call the property node to set the X coordinate of the cursor to 1, read the Y value of the cursor, which is the voltage value 1 second after the power supply is disconnected, and modify the X coordinate value of the cursor to determine the voltage value at other times after the power supply is disconnected. Finally, determine whether the standard requirements are met. If not, an alarm is issued, and the charge value of the EUT is calculated according to Q=CU, where C is the capacitance value of the EUT circuit and U is the voltage value 1 second after the power supply is disconnected.

[0112] The test software sends corresponding instructions to the relay module through the RS232 serial port according to the communication protocol provided by the relay module, sets the status of the 4th, 5th, 6th, 7th, 10th, and 11th relays to OFF, uses the LN voltage waveform as the trigger waveform, calls the "power supply automatically disconnects at the peak / trough position of the voltage waveform" subroutine, disconnects the power supply at the peak / trough, and uses the CH0, CH1, and CH2 channels of the data acquisition module to collect the voltage waveform data of the LN, EN, and WN terminals respectively. The waveform data between all ports is obtained by calculation:

[0113] waveformdata(ln)=waveformdata(ln);

[0114] Waveform data (LE) = waveform data (LN) - waveform data (EN);

[0115] Waveform data (LW) = waveform data (LN) - waveform data (WN);

[0116] Waveform data (NE) = -waveform data (EN);

[0117] Waveform data (NW) = -waveform data (WN);

[0118] Waveform data (EW) = waveform data (EN) - waveform data (WN).

[0119] Call the "Create Waveform" function in LabVIEW to generate all test waveforms, call the "Waveform Graph" control in LabVIEW to display the test waveforms. Finally, use the test waveform acquisition and the voltage value calculation method after the power supply is disconnected for 1 second to calculate the voltage value after 1 second.

[0120] At present, most of the industry uses a larger resistor to simulate the open circuit state, and the EUT power socket discharges the resistor. However, even a larger resistor is not equivalent to an open circuit, so it will have a certain impact on the test results, resulting in inaccurate results. The present invention proposes two test modes for realizing the open circuit test.

[0121] First mode:

[0122] The test software calls the "power supply automatically disconnects at the peak / trough position of the voltage waveform" subroutine, and sends corresponding instructions to the relay module through the RS232 serial port to set the status of the 1st, 2nd, and 3rd relays to ON. While disconnecting the power supply, send corresponding instructions to the relay module to set the status of the 8th, 9th, 10th, and 11th relays to ON, disconnect the data acquisition module, make the discharge circuit of the EUT open, and start timing at the same time. After waiting for 0.9 seconds, send corresponding instructions to the relay module to set the status of the 8th, 9th, 10th, and 11th relays to OFF, close the data acquisition module, collect the test waveform, and calculate the voltage value 1 second after the power supply is disconnected.

[0123] Second mode:

[0124] The method is similar to the first test mode, except that multiple tests are required. The data acquisition module is closed at 0.1 seconds, 0.2 seconds, 0.3 seconds, 0.4 seconds, 0.5 seconds, 0.6 seconds, 0.7 seconds, 0.8 seconds, 0.9 seconds, 1.0 seconds, 1.2 seconds, 1.3 seconds, 1.4 seconds, and 1.5 seconds after the power supply is disconnected. The acquisition time can be shortened appropriately each time, and only the voltage value at the disconnection time is taken each time. After all 15 tests are completed, these data are used to generate waveforms, and the "waveform resampling" function in LabVIEW is called to upgrade the sampling rate of the waveform to 10kSa / s, which is the same as the data acquisition module. Then this waveform replaces the waveform from the power supply disconnection to 1.5 seconds after the power supply is disconnected in the original test waveform, and the voltage value 1.0 seconds after the power supply is disconnected is used as the voltage value measurement value 1 second after the power supply is disconnected. The test time interval and test number can be adjusted according to actual conditions.

[0125] The first mode only needs one test, which has the advantages of fast test speed and high efficiency, but can only get the voltage value 1 second after the power supply is disconnected, and cannot get the discharge waveform. The second mode can get the voltage value 1 second after the power supply is disconnected and can also get the discharge waveform to observe the discharge trend of the EUT, but the number of tests is large, which affects the test efficiency. You can choose the test mode according to the actual situation when using it.

[0126] If the disconnection time of the power supply is found to be inaccurate during the test, resulting in the voltage waveform not being disconnected at the peak / trough position, the calibration procedure can be used to adjust the time △t 2 Make corrections.

[0127] The test software calls the subroutine of "automatically disconnecting the power supply at the peak / trough position of the voltage waveform", collects the test waveform, and uses the "acquire waveform subset" function in LabVIEW to intercept the waveform before the power supply is disconnected, that is, the sine wave. Then reverse the waveform data, regenerate the waveform, call the "extract single-frequency information" function in LabVIEW to measure the frequency and phase of the voltage waveform, and the time difference △t between the starting moment of the waveform and the positions of the peak and trough can be calculated through the phase and frequency. 4 and △t 5 , if △t 4 <△t 5 and △t 4 <T / 2, then △t 4 =△t 4 + T, where T is the period of the voltage waveform. Test about 20 times to obtain 20 △t 4 . First, use Dixon's rule to剔除 all outliers, and then take the average value △t 4（平均） of the remaining data. Use △t 2 =△t 2 -△t 4（平均） . Finally, if △t 2 <0, then △t 2 =△t 2 +T until △t 2 is between 0 and T. The number of tests can be adjusted according to the actual situation.

[0128] To prevent the response time of the relay from drifting over time, resulting in the voltage waveform being disconnected at a position other than the peak / trough after a long time, the present invention proposes a test mode of testing and correcting simultaneously.

[0129] During each test process, use the method of "adjusting time △t 2 correction" to calculate the time difference △t 4 of the current test, and use this value to correct the adjustment time △t 2 , that is, △t 2 =△t 2 -△t 4（平均） . Finally, if △t 2 <0, then △t 2 =△t 2 +T until △t 2 is between 0 and T. This test mode can effectively avoid test errors caused by the response time of the relay aging and drifting over time.

[0130] The present invention can realize the fully automatic test of the residual voltage of medical electrical equipment. The present invention not only realizes the automatic disconnection at the peak / trough of the power supply waveform, automatically collects the test waveform, and calculates the voltage value 1 second (or n seconds) after the power supply is disconnected; it also has multiple test modes, and can realize the simultaneous test of all test channels in any combination of the L, N, ground three-pole and the four terminals of the shell of the tested device; compared with traditional test equipment, the present invention also supports open circuit testing, and the test results are more accurate. It also has the characteristics of high test efficiency, high test accuracy, strong anti-interference ability, and support for self-correction.

[0131] The residual voltage measuring device for medical equipment provided by the present invention has the following beneficial effects:

[0132] 1) It can realize automatic disconnection at the peak / trough of the power supply waveform without repeating the operation about 10 times. The test efficiency is high, which greatly saves manpower and time, and has higher test accuracy;

[0133] 2) The residual voltage of the tested port can be tested by triggering the relay through the voltage wave of other ports, which is powerful;

[0134] 3) It can automatically generate the test waveform and calculate the voltage value 1 second (or n seconds) after the power supply is disconnected, with high test efficiency;

[0135] 4) It can realize simultaneous testing of all test channels in any combination of the L, N and ground three-pole of the device under test plug and the four terminals of the device under test shell, with high testing efficiency;

[0136] 5) The relay connection method adopted can effectively avoid the short circuit between the L (live wire) of the power supply and other terminals, ensuring the safety of the test;

[0137] 6) It can realize true open circuit test, and the test results are more accurate;

[0138] 7) It can realize self-calibration to ensure the accuracy of test results;

[0139] 8) Support the test mode of testing and correcting at the same time;

[0140] 9) The voltage acquisition has high accuracy, the waveform distortion is small, and the test results are more accurate;

[0141] 10) It has strong anti-power frequency interference capability, the test waveform is more realistic and the test result is more accurate.

[0142] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A residual voltage measuring device for medical equipment, characterized in that: include: A control module, a relay module, a data acquisition module and a display device; the relay module includes a plurality of relays; The control module sends a control instruction to the relay module and sends a collection instruction to the data collection module; The relay module is switched to a test state according to the control instruction; in the test state, the three poles of the plug of the device under test and the shell of the device under test are respectively connected to the relay module, the power supply and the data acquisition module; The data acquisition module acquires the test voltage waveform according to the acquisition instruction and sends it to the control module; The control module determines the positions of the peak and the trough according to the initial phase of the test voltage waveform, generates a start-stop instruction and a re-collection instruction according to the positions of the peak and the trough, controls the designated relay to be disconnected according to the start-stop instruction, and controls the data collection module to re-collect the test voltage waveform according to the re-collection instruction; And, the control module tests the re-collected test voltage waveform to generate a display test result, and sends the display test result to the display device; The display device is used to output the display test result; the display test result is a voltage value, or a voltage value and a discharge waveform; The control module controls the opening and closing of a specified relay in the relay module so that when the power supply is disconnected, the connection between the data acquisition module and the three-pole plug of the device under test and the housing of the device under test is disconnected at the same time, thereby realizing an open circuit test; Generating the start-stop command according to the position of the peak and the trough includes: calling the "high-precision polling wait" function in LabVIEW, setting the delay time to △t2-△t1, and sending the start-stop command to the relay module via the RS232 serial port, so that the power supply is disconnected at the peak or trough of the voltage waveform; Among them, △t1 is the time difference between the starting time of the voltage waveform and the peak position, and △t2 is the adjustment time; The relay module includes at least 11 relays; The L terminal of the power plug of the device under test is simultaneously connected to the common terminal of the first relay and the normally closed terminal of the fourth relay; The N terminal of the power plug of the device under test is simultaneously connected to the common terminal of the second relay and the normally closed terminal of the sixth relay; The ground terminal of the power plug of the device under test is simultaneously connected to the common terminal of the third relay, the normally open terminal of the fifth relay, the normally open terminal of the sixth relay, and the normally closed terminal of the tenth relay; The housing of the device under test is simultaneously connected to the normally open terminal of the 7th relay and the normally closed terminal of the 11th relay.

2. The residual voltage measuring device according to claim 1, characterized in that: The control module controls the opening and closing of a specified relay in the relay module so that any combination of the three-pole plug of the device under test and the housing of the device under test can be tested for a single test channel, or all test channels can be tested simultaneously.

3. The residual voltage measuring device according to claim 1, characterized in that: The input resistance of the data acquisition module is greater than or equal to 100 MΩ; The data acquisition module has at least three acquisition channels; The voltage acquisition range of the data acquisition module includes at least -400V to 400V; The sampling frequency of the data acquisition module is greater than or equal to 1kHz; The continuous sampling time of the data acquisition module is greater than or equal to 2 seconds.

4. The residual voltage measuring device according to claim 1, characterized in that: The L terminal of the power supply is connected to the normally closed terminal of the first relay; The N terminal of the power supply is connected to the normally closed terminal of the second relay; The ground terminal of the power supply is connected to the normally closed terminal of the third relay.

5. The residual voltage measuring device according to claim 4, characterized in that: The positive terminal of the CH0 channel of the data acquisition module is connected to the common terminal of the 8th relay; The positive terminal of the CH1 channel of the data acquisition module is connected to the common terminal of the 10th relay; The positive terminal of the CH2 channel of the data acquisition module is connected to the common terminal of the 11th relay; The negative terminal of the CH0 channel, the negative terminal of the CH1 channel, and the negative terminal of the CH2 channel of the data acquisition module are simultaneously connected to the common terminal of the ninth relay.

6. The residual voltage measuring device according to claim 5, characterized in that: The common terminal of the 4th relay is connected to the normally closed terminal of the 5th relay; The common terminal of the 5th relay is connected to the normally closed terminal of the 8th relay; The common terminal of the 6th relay is connected to the normally closed terminal of the 7th relay; The common terminal of the 7th relay is connected to the normally closed terminal of the 9th relay; The normally open terminals of the 1st relay, the 2nd relay, the 3rd relay, the 8th relay, the 9th relay, the 10th relay and the 11th relay are suspended.

7. The residual voltage measuring device according to claim 6, characterized in that: The first relay, the second relay and the third relay are used to control the on and off of the power supply; The 8th relay, the 9th relay, the 10th relay and the 11th relay are used to control the on and off of the CH0 channel, the CH1 channel and the CH2 channel of the data acquisition module respectively; The 4th relay, the 5th relay, the 6th relay and the 7th relay are respectively used to control and select different test channels.

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