A wired operable display system for an instrument

Abstract

The application discloses a wired operable display system of an instrument, and belongs to the technical field of wired data acquisition and transmission.The application comprises: a power supply for supplying power to the system; an instrument end for measuring various parameters of an instrument and converting the parameters into I2C bus signals, which are sent to a display end after buffering and driving; a shielding wire serving as a transmission wire of the I2C bus signals and the power supply between the instrument end and the display end; and the display end for receiving the I2C bus signals, converting the signals into digital signals, and displaying the signals on a display screen.The application has higher convenience and reliability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wired data acquisition and transmission, and particularly relates to a wired operable display system of instruments and meters. BACKGROUND

[0002] In modern process industry, many installed instruments are not equipped with digital display, or are equipped with display modules but are not conducive to personnel observation (for example, the instruments are installed on the top of tanks more than ten meters high or in high-temperature dangerous areas, etc.), at this time, the data collected by the measuring instruments is transmitted to the background control system, and the workers on site cannot conveniently and timely understand the conditions of the materials in the tank and the data collected by the measuring instruments. There are the following two types of external display modules for mainstream instruments:

[0003] The first type is directly connected to the bus, and this display module is also called a tank-side meter and displays data by collecting bus data. This display module has extremely small power consumption and low cost, and the disadvantage is that the data display of the tank-side meter can only read specific signals and does not support other protocol forms, and for composite signals, multiple tank-side meters may be needed for collection and display, and the use convenience is poor.

[0004] The second type is to directly make the external display module into a relatively independent wireless instrument, and use wireless technology to complete signal reception and transmission. This display module is very portable to install, has long transmission distance, and can remotely control the instrument, and the disadvantage is that the signal is greatly affected by the environment and has poor reliability. SUMMARY

[0005] The purpose of the present application is to solve the problems existing in the prior art, and to provide a wired operable display system of instruments and meters, which has higher use convenience and reliability.

[0006] The purpose of the present application is achieved by the following technical solutions:

[0007] A wired operable display system of instruments and meters, comprising:

[0008] A power supply for supplying power to the system;

[0009] An instrument end for measuring various parameters of the instrument and converting them into I2C bus signals, which are buffered and driven to be sent to

[0010] A display end;

[0011] Shielded wires as transmission wires of I2C bus signals and power supply between the instrument end and the display end;

[0012] A display end for receiving I2C bus signals and converting them into digital signals, which are displayed through a display screen.

[0013] As preferred, the instrument end comprises:

[0014] a power management module for converting input power into power available for each module and outputting a 4-20mA current signal under the control of the first microprocessor module;

[0015] a sensor module for measuring various parameters of the instrument;

[0016] a first microprocessor module for converting analog signals measured by the sensor module into digital signals, controlling the power management module to output a 4-20mA current signal according to the digital signals, and converting the 4-20mA current signal into an I2C bus signal; and transmitting the digital signals into the first signal generation module;

[0017] a first signal generation module for modulating the digital signals transmitted by the first microprocessor module and coupling them into the 4-20mA current signal output by the power management module;

[0018] a first transceiver module for buffering and driving the I2C bus signal of the first microprocessor module and transmitting it to the display end.

[0019] As preferred, the first signal generation module is also used for decoupling the analog signals transmitted on the I2C bus from the power management module, demodulating the analog signals and transmitting them into the first microprocessor module.

[0020] As preferred, the first transceiver module is also used for receiving the I2C bus signal from the display end.

[0021] As preferred, the display end comprises:

[0022] a second transceiver module for receiving the I2C bus signal from the instrument end and transmitting it into the second microprocessor module;

[0023] a second microprocessor module for converting the I2C signal from the second transceiver module into a digital signal and transmitting it into the display screen module;

[0024] a display screen module for processing the digital signal from the second microprocessor module and displaying it.

[0025] As preferred, the display end comprises:

[0026] a switch module for receiving the switch signal input by the user and transmitting it into the second microprocessor module; the second microprocessor module is also used for converting the switch signal into an I2C bus signal and transmitting it into the second transceiver module; the second transceiver module is also used for buffering and driving the I2C bus signal from the second microprocessor module and transmitting it to the instrument end.

[0027] Preferably, the display terminal includes:

[0028] A boost switching power supply module is used to boost the power from the instrument to the voltage required by the display.

[0029] Preferably, a relay transceiver is included, and both the instrument end and the display end are equipped with transceivers. The relay transceiver is connected to both transceivers via the shielded cable.

[0030] Preferably, an I2C bus and a control signal line are provided between the instrument terminal and its transceiver, and between the display terminal and its transceiver. The control signal line is used to control the transmission and reception status of the transceiver.

[0031] Preferably, the instrument terminal and the display terminal use an APL bus for signal transmission.

[0032] The advantages of this invention are:

[0033] 1. Transmitting signals via the I2C bus instead of the power bus can meet the transmission requirements of composite signals and improve ease of use; at the same time, the effective transmission distance can reach more than 30 meters, which can be further extended through repeater transceivers, resulting in higher reliability;

[0034] 2. High versatility, applicable to various existing transmitters and instruments;

[0035] 3. The signal is driven by a transceiver, which can achieve a balance between driving capability and power consumption. Attached Figure Description

[0036] Figure 1 This is a configuration block diagram of a wired operable display system for an instrument provided in Embodiment 1 of this specification;

[0037] Figure 2 This is a block diagram of the transceiver configuration provided in Embodiment 2 of this specification;

[0038] Figure 3 This is a configuration block diagram of a wired operable display system for an instrument provided in Embodiment 3 of this specification. Detailed Implementation

[0039] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0040] Example 1

[0041] like Figure 1 As shown, this embodiment provides a wired operable display system for instruments and meters, including:

[0042] The power supply is used to provide power to the system;

[0043] Instrument end, for measuring various parameters of the instrument and converting into I2C bus signals, after buffering and driving, transmitting to

[0044] Display end;

[0045] Shielding line, as the transmission line of I2C bus signals and power supply between the instrument end and the display end;

[0046] Display end, for receiving I2C bus signals, and after converting into digital signals, displaying through the display screen.

[0047] The embodiment transmits signals through I2C bus instead of power supply bus, can meet the transmission demand of composite signals, and improves the use convenience; meanwhile, the effective transmission distance can reach more than thirty meters, and the reliability is higher. The parts of the system are introduced in detail as follows.

[0048] The power supply can adopt an independent external power supply or a power supply line of the upper computer and the lower computer, and provides 24V DC power supply.

[0049] The instrument end comprises:

[0050] The power management module is used for converting the input 24V power supply into 3.3V power supply available for each module, and outputting 4-20mA current signal under the control of the first microprocessor module;

[0051] The sensor module can contain multiple sensors arranged inside or outside the instrument, and is controlled by the first microprocessor module, and is used for measuring multiple physical quantities such as temperature, pressure, and material level, and transmitting the analog signals converted from the physical quantities into the first microprocessor module;

[0052] The first microprocessor module is used for converting the analog signals measured by the sensor module into digital signals, on one hand, controlling the power management module to output 4-20mA current signal according to the digital signals, and converting the 4-20mA current signal into I2C bus signals; on the other hand, transmitting the digital signals into the first signal generation module;

[0053] The first signal generation module is generally used for transmitting HART signals, on one hand, decoupling the analog signals transmitted by the I2C bus from the power management module, and transmitting the demodulated analog signals into the first microprocessor module; on the other hand, modulating the digital signals transmitted from the first microprocessor module, and coupling into the 4-20mA current signal output by the power management module;

[0054] The first transceiver module leads out a pair of I2C buses on the first microprocessor module, buffers, drives and transceives the pair of I2C buses, and guarantees that the I2C signals of the first microprocessor can be completely transmitted to the display end.

[0055] The shielding wire is a four-channel transmission wire with a shielding function, and the length is generally 0-30 m. The four channels are:

[0056] The power line is a power line connecting the instrument end and the display end. The power supply is generated by the power management module of the instrument end, and the initial voltage is 3.3 V. However, the voltage will be consumed after being used by multiple modules and being transmitted for a long distance.

[0057] The SCL clock line is responsible for transmitting bidirectional clock signals.

[0058] The SCL data line is responsible for transmitting bidirectional data signals.

[0059] The ground wire is a ground wire connecting the reference ground between the instrument end and the display end. The ground wire is not connected to the ground.

[0060] The display end includes:

[0061] The second transceiver module leads out a pair of I2C buses on the second microprocessor module, buffers, drives and transceives the pair of I2C buses, and guarantees that the I2C signals of the second microprocessor can be completely transmitted to the instrument end. The second transceiver module can also receive I2C signals from the instrument end.

[0062] The second microprocessor module is used to convert the I2C signals from the second transceiver module into digital signals and transmit the digital signals into the display screen module. The second microprocessor module is also used to receive switch signals from the switch module, convert the switch signals into I2C bus signals, and transmit the I2C bus signals into the second transceiver module.

[0063] The display screen module is used to process the digital signals from the second microprocessor module and display the digital signals.

[0064] The switch module is composed of multiple touch switches (buttons) and generates interactive commands by being pressed by the user and transmitting the interactive commands into the second microprocessor module.

[0065] The boost switching power supply module is used to compensate for the voltage after long-distance transmission and stabilize the voltage to 3.3 V.

[0066] In summary, the working principle of the embodiment is as follows:

[0067] First, the whole system is powered on, 24V power supply is turned on, power management module starts to work, the 24V input power supply voltage is converted into a more stable 3.3V voltage, which is used to supply power to each module. If there is another power supply requirement, another voltage can be converted by the power supply module to supply power.

[0068] 3.3V voltage is generated, the first microprocessor module of the center starts to work, the first microprocessor module enables the sensor outside or inside the instrument to start collecting the physical quantities such as temperature, pressure, level, etc. that need to be collected, and then transmits them to the first microprocessor module.

[0069] The first microprocessor module converts it into a digital signal, which is transmitted to the signal generator. The signal generator (mainly HART signal generator) modulates the signal into a signal of 1200 Hz (representing 1) and 2200 Hz (representing 0), and the amplitude is generally ±0.5 mA. It is coupled to the 4-20 mA current signal output by the power management module two-line output to output the signal. On the other hand, the digital signal can be used to control the 4-20 mA output of the power management module, and further processing can be performed in the first microprocessor module to become an I2C bus signal and enter the first transceiver module.

[0070] After the I2C bus signal enters the first transceiver module, the first transceiver module buffers and drives it, and then inputs it into the second transceiver module of the external display terminal through a certain length of shielded wire together with a pair of 3.3V and ground power lines. The 3.3V power signal line is input into the boost switching power supply module to be boosted to a stable 3.3V power supply.

[0071] The second transceiver module transmits the I2C bus signal into the second microprocessor module, which performs analog-to-digital conversion, and then the digital signal enters the display screen module to participate in display. Users can observe the temperature, level, pressure and other information measured by the instrument through the display screen, and can also view the measurement curve and historical records.

[0072] At the same time, the above signal flow is reversible, so users can operate through the buttons on the switch module of the display terminal. The switch signal enters the second microprocessor module, which can participate in the control of the display function of the display screen, and can also enter the first microprocessor of the instrument terminal through the second transceiver module to participate in the control of the sensor module. When the power is provided by the upper / lower computer, the signal transmitted from the display terminal can be coupled into the power line through the signal generation module to configure the upper / lower computer at a distance.

[0073] Second, when the power supply is not only independent external power supply, but also the entire industrial control system, when the host / PC to change the configuration of the instrument, the signal directly coupled into the power line of the instrument, after decoupling through the power management module into the signal generation module, signal generation module demodulation after the signal into the first microprocessor module, the first microprocessor module can control change the configuration of the sensor module, but also can be transmitted through the first transceiver into the external display end, into the second microprocessor module, and then communicate with the display module, change the display content or interface configuration of the display screen.

[0074] Example 2

[0075] When the field environment has higher requirements for transmission distance and signal protection, the transceiver of the instrument end and the display end needs to be incrementally designed.

[0076] As Figure 2 shown, after the external 50m shielding line, the specific configuration of the first transceiver module and the second transceiver module, and a relay transceiver is arranged in the middle of the shielding line for amplifying the signal, so as to balance the extension of the signal transmission distance and the reliability of the signal transmission.

[0077] The configuration of the first transceiver module and the second transceiver module is completely consistent, and the first transceiver module is taken as an example for description. The first transceiver module is powered by a 3.3V power supply and a ground, and is connected with six signal lines. The upper left group of lines is the clock line and the data line of the I2C bus, which are pulled up by larger resistors (K level) R1 and R2, respectively. The lower left group of lines is the transmission direction control signal line, and the two lines correspond to the clock control signal and the data control signal, respectively. When the pin input is "0", the transceiver only receives but does not transmit, and when the pin input is "1", the transceiver only transmits but does not receive. The above-mentioned control signal line is only for external communication, that is, the communication between the instrument end and the display end. The internal communication is not controlled by the tri-state gate, but is free to receive and transmit, that is, the communication between the first transceiver module and the first microprocessor module. The control transceiver is to prevent the risk and competition of the transceiver signal. Here, R3 and R4 are used to pull down the signal, so that it is in a low level state when there is no control signal input, that is, only receiving but not transmitting, to ensure normal signal reception. Only when the pin input is "1", the state is switched to only transmitting but not receiving, and the external signal transmission is allowed. The right group of lines of the first transceiver module is connected with the relay transceiver, and corresponds to the clock signal and the data signal, respectively, for external communication. Since the external transmission line is long and has high parasitic capacitance, small resistors (hundred-ohm level) R5 and R6 are needed to pull up the signal.

[0078] The repeater transceiver has a set of signal lines on both the left and right sides, which are connected to the first transceiver module and the second transceiver module respectively. The connection lines on both sides are 25 meters long, so small resistors (hundreds of ohms) R7-R10 are needed to pull them high for driving. The repeater transceiver is a slave transceiver, so there will be no risk or contention, and therefore there is no need to control its transmission and reception.

[0079] To make it easier to understand, here are two more working states:

[0080] Shortly after the circuit is powered on, the sensor module performs measurements and converts the data into I2C bus signals via the first microprocessor module. Simultaneously, the first microprocessor module sends a transmit permission command to the first transceiver module. Upon receiving the command and the I2C bus signal, the first transceiver module drives the signal and transmits it to the relay transceiver. The relay transceiver continues to drive the signal, transmitting the I2C bus signal to the second transceiver module. At this point, the second transceiver module is in a receive-only state, so it receives the signal and then sends it to the second microprocessor module. The second microprocessor module then turns on the display screen and begins to show the sensor's test results.

[0081] When the user operates the button, the switch data is converted into an I2C bus signal by the second microprocessor module. At the same time, the second microprocessor sends a transmit permission command to the second transceiver module. Upon receiving the command and the I2C bus signal, the second transceiver module drives the signal and sends it to the relay transceiver. The relay transceiver continues to drive the signal and sends the I2C bus signal to the first transceiver module. At this time, the first transceiver module is in a receive-only state, so it receives the signal and then sends it to the first microprocessor module. The first microprocessor module can then change the sensor configuration according to the signal command.

[0082] Example 3

[0083] like Figure 3 As shown, if the field end has a transmission requirement exceeding 30m and is not suitable for multiple repeaters, an APL bus can be used instead of an I2C bus for signal transmission. The difference from Example 1 is that the first and second transceiver modules are replaced with APL modules that can convert other signals into APL signals, and the four transmission lines connecting the two transceivers are replaced with a single Category 4 cable consisting of four twisted pairs. Due to the advantages of APL communication, the transmission distance can reach over 100 meters.

[0084] The above merely describes preferred specific embodiments of the present application, which is based on one implementation of the overall concept of the present application, and the protection scope of the present application is not limited thereto, any changes or replacements that can be easily conceived by those skilled in the art within the technical scope disclosed by the present application shall be covered within the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A wired operable display system for an instrument, characterized in that, The utility model relates to a kind of digital display instrument, including: Power supply for supplying power to the system; Instrument end for measuring various parameters of the instrument and converting into I 2C bus signal, after buffering and driving, it is sent to display end;The instrument end includes: Power management module for converting input power into power available to each module and outputting 4-20mA current signal under the control of the first microprocessor module; Sensor module for measuring various parameters of the instrument; First microprocessor module for converting analog signal measured by sensor module into digital signal, controlling power management module to output 4-20mA current signal according to the digital signal, and converting 4-20mA current signal into I2C bus signal;While the digital signal is transmitted into the first signal generation module; First signal generation module for modulating digital signal transmitted from the first microprocessor module and coupling into 4-20mA current signal output by power management module; First transceiver module for buffering and driving I2C bus signal of the first microprocessor module and sending to the display end; Shielded wire as transmission wire of I2C bus signal and power between instrument end and display end; Display end for receiving I2C bus signal and converting into digital signal, then displaying through display screen, the display end includes: Second transceiver module for receiving I2C bus signal from the instrument end and transmitting into the second microprocessor module; Second microprocessor module for converting I2C signal from the second transceiver module into digital signal and transmitting into the display screen module; Display screen module for displaying after processing digital signal from the second microprocessor module; Relay transceiver connected between the first transceiver module and the second transceiver module through the shielded wire; I2C bus and control signal line are provided between the first transceiver module and the first microprocessor module, and between the second transceiver module and the second microprocessor module, when control signal line inputs "0" to transceiver module, transceiver module only receives but does not transmit to relay transceiver, when control signal line inputs "1" to transceiver module, transceiver module only transmits but does not receive to relay transceiver. The first signal generation module is also used for decoupling analog signal transmitted on I2C bus from the power management module, and transmitting the demodulated analog signal into the first microprocessor module.

2. An instrument wired operable display system as claimed in claim 1, wherein, The first transceiver module is also used for receiving I2C bus signal from the display end.

3. An instrument wired operable display system as claimed in claim 1, wherein, The display end includes:

4. An instrument wired operable display system as claimed in claim 1, wherein, Switch module for receiving switch signal input by user and transmitting into the second microprocessor module;The second microprocessor module is also used for converting switch signal into I2C bus signal and transmitting into the second transceiver module;The second transceiver module is also used for buffering and driving I2C bus signal from the second microprocessor module and sending to the instrument end. The display end includes:

5. An instrument wired operable display system as claimed in claim 1, wherein, Boost switching power supply module for boosting power from the instrument end to the voltage required by display end. APL bus is used for signal transmission between the instrument end and the display end.

6. An instrument wired operable display system as claimed in claim 1, wherein, ​

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