SMT tray detection circuit

Abstract

The utility model relates to an SMT (Surface Mount Technology) tray detection circuit, which comprises a receiving module, a transmitting module, an amplification comparison module and a control module, the receiving module comprises a receiving switch unit and a plurality of receiving circuits, the plurality of receiving circuits are connected with the receiving switch unit, and the receiving switch unit is respectively connected with the amplification comparison module and the control module; the transmitting module comprises a transmitting switch unit and a plurality of transmitting circuits, the plurality of transmitting circuits are connected with the transmitting switch unit, and the transmitting switch unit is connected with the control module; the amplification comparison module comprises an amplification unit and a comparison unit, the amplification unit is connected with the receiving switch unit, and the comparison unit is connected with the amplification unit and the control module. According to the utility model, through optimized circuit design, the circuit capable of detecting a large number of SMT material trays is realized, the circuit expansibility is good, the hardware resource requirement is low, the cost is low, and the circuit is especially suitable for the detection of high-transparency SMT material trays.

Description

Technical Field

[0001] This utility model relates to a detection circuit, and more particularly to an SMT tray detection circuit. Background Art

[0002] Currently, the detection of the presence or absence of SMT trays in SMT feeding equipment typically employs a transmitter and receiver system at each tray slot. The transmitter emits a signal, which is then received by the receiver. The receiver compares the signal value when the SMT tray slot is empty with the value when a tray is present, and outputs a presence / absence signal. Each tray slot corresponds to a data acquisition channel, and the MCU controller directly acquires and outputs control signals from each channel. Since such SMT feeding equipment has a large number of tray slots (up to 1400), this method places high demands on the MCU controller's ADC channels and I / O ports, resulting in high hardware resource requirements, complex circuit structure, and high cost. In addition, since some SMT trays are made of highly transparent acrylic material, the difference between the detection signals when the SMT tray position is empty and when the SMT tray position has such a highly transparent tray is very small. This increases the difficulty of detection and makes it easy to trigger false triggers and lead to misjudgment. Summary of the Invention

[0003] The technical problem to be solved by this utility model is to provide an SMT tray detection circuit, which provides a hardware circuit for detecting a large number of SMT trays, especially for detecting high transparency trays.

[0004] To address this issue, this utility model provides an SMT tray detection circuit, comprising: a receiving module, a transmitting module, an amplification and comparison module, and a control module; the receiving module includes a receiving switch unit and multiple receiving circuits, all of which are connected to the receiving switch unit, and the receiving switch unit is connected to both the amplification and comparison module and the control module; the transmitting module includes a transmitting switch unit and multiple transmitting circuits, all of which are connected to the transmitting switch unit, and the transmitting switch unit is connected to the control module; the amplification and comparison module includes an amplification unit and a comparison unit, the amplification unit being connected to the receiving switch unit, and the comparison unit being connected to both the amplification unit and the control module.

[0005] A further improvement of this invention is that the number of receiving circuits is equal to the number of transmitting circuits, and the receiving circuits correspond one-to-one with the transmitting circuits.

[0006] A further improvement of this utility model is that the receiving switch unit includes a first multi-channel bidirectional analog switch, which is connected to the receiving circuit; the transmitting switch unit includes a second multi-channel bidirectional analog switch, which is connected to the transmitting circuit.

[0007] A further improvement of this utility model is that the first multi-channel bidirectional analog switch includes a first enable port and multiple first gating ports; the first enable port and multiple first gating ports are connected to the control module.

[0008] A further improvement of this utility model is that the number of the first multi-channel bidirectional analog switches is multiple; the multiple first multi-channel bidirectional analog switches are connected in parallel with each other through the first gating port and then connected to the control module; the first enable ports of the multiple first multi-channel bidirectional analog switches are respectively connected to the control module.

[0009] A further improvement of this invention is that the second multi-channel bidirectional analog switch includes a second enable port and multiple second gating ports; the second enable port and multiple second gating ports are connected to the control module.

[0010] A further improvement of this utility model is that the number of the second multi-channel analog switches is multiple; the multiple second multi-channel bidirectional analog switches are connected in parallel with each other through the second gating port and then connected to the control module; the second enable ports of the multiple second multi-channel analog switches are respectively connected to the control module.

[0011] A further improvement of this invention is that the amplification unit includes a multi-stage amplification circuit and a DC blocking capacitor; one end of the DC blocking capacitor is connected to the receiving switch unit, and the other end of the DC blocking capacitor is connected to the multi-stage amplification circuit.

[0012] A further improvement of this utility model is that the comparison unit includes a comparator, an adjustable potentiometer, a reference voltage source, a first voltage divider resistor, and a second voltage divider resistor; one end of the first voltage divider resistor is connected to the reference voltage source, and the other end of the first voltage divider resistor is connected to the non-inverting input terminal of the comparator and one end of the adjustable potentiometer, respectively; the other end of the adjustable potentiometer is grounded through the second voltage divider resistor; the inverting input terminal of the comparator is connected to the amplification unit; and the output terminal of the comparator is connected to the control module.

[0013] Compared with the prior art, the beneficial effects of this utility model are as follows: through optimized circuit design, this utility model realizes an SMT tray detection circuit, which provides a hardware foundation for solving the detection of a large number of SMT trays. In particular, the detection circuit structure is better for high transparency trays. Moreover, this circuit has good scalability, requires fewer hardware resources, and has a lower cost. Attached Figure Description

[0014] Figure 1 This is a schematic block diagram of a circuit module according to one embodiment of the present invention;

[0015] Figure 2 This is a circuit schematic diagram of the receiving module according to one embodiment of the present invention;

[0016] Figure 3 This is a circuit diagram of the transmitting module according to one embodiment of the present invention;

[0017] Figure 4 This is a circuit schematic diagram of the control module of one embodiment of the present invention;

[0018] Figure 5 This is an optimized circuit schematic diagram of the receiving switch unit according to one embodiment of the present invention;

[0019] Figure 6 This is an optimized circuit schematic diagram of the transmitter switch unit according to one embodiment of the present invention;

[0020] Figure 7 This is a circuit diagram of an amplification and comparison module according to one embodiment of the present invention;

[0021] Figure 8 This is a schematic diagram of a practical scenario of one embodiment of the present invention.

[0022] Figure labels: 1-Receiver module; 101-Receiver switch unit; 102-Receiver circuit; 2-Transmitter module; 201-Transmitter switch unit; 202-Transmitter circuit; 3-Amplification and comparison module; 301-Amplification unit; 3011-Multi-stage amplifier circuit; 302-Comparison unit; 4-Control module; 5-Panel; 6-SMT tray position; 7-Transmitter; 8-Receiver; 9-Isolation block; 10-Signal absorption board; 11-Circuit board. Detailed Implementation

[0023] In the description of this utility model, if directional descriptions are involved, such as "up," "down," "front," "back," "left," "right," etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, it is only for the convenience of describing this utility model and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. If a certain technical feature is referred to as "set," "fixed," "connected," or "installed" on another technical feature, it can be directly set, fixed, or connected to the other technical feature, or it can be indirectly set, fixed, connected, or installed on the other technical feature.

[0024] In the description of this utility model, the term "several" means one or more; the term "multiple" means two or more; the terms "greater than," "less than," and "exceeding" should be understood as excluding the stated number; and the terms "above," "below," and "within" should be understood as including the stated number. The terms "first," "second," etc., should be understood as being used only to distinguish identical or similar technical feature names, and should not be interpreted as implying / indicating the relative importance of the technical features, the number of technical features, or the sequential relationship between the technical features.

[0025] The preferred embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0026] like Figure 1 As shown, this embodiment provides an SMT tray detection circuit, including: a receiving module 1, a transmitting module 2, an amplification and comparison module 3, and a control module 4; the receiving module 1 includes a receiving switch unit 101 and multiple receiving circuits 102, all of which are connected to the receiving switch unit 101, and the receiving switch unit 101 is connected to the amplification and comparison module 3 and the control module 4 respectively; the transmitting module 2 includes a transmitting switch unit 201 and multiple transmitting circuits 202, all of which are connected to the transmitting switch unit 201, and the transmitting switch unit 201 is connected to the control module 4; the amplification and comparison module 3 includes an amplification unit 301 and a comparison unit 302, the amplification unit 301 is connected to the receiving switch unit 101, and the comparison unit 302 is connected to the amplification unit 301 and the control module 4 respectively.

[0027] like Figure 2 and Figure 3 As shown, the number of receiving circuits 102 is equal to the number of transmitting circuits 202, and the receiving circuits 102 and the transmitting circuits 202 correspond one-to-one.

[0028] More specifically, the multiple receiving circuits 102 have the same circuit structure, and the multiple transmitting circuits 202 also have the same circuit structure. The multiple transmitting circuits 202 transmit detection signals through light-emitting diodes D1 to D8, and the multiple receiving circuits 102 receive detection signals through phototransistors Q1 to Q8, with each light-emitting diode D1 to D8 corresponding to a phototransistor Q1 to Q8.

[0029] like Figure 2 and Figure 3As shown, the receiving switch unit 101 includes a first multi-channel bidirectional analog switch U3, which is connected to the receiving circuit 102; the transmitting switch unit 201 includes a second multi-channel bidirectional analog switch U2, which is connected to the transmitting circuit 202.

[0030] like Figure 2 and Figure 4 As shown, in this embodiment, the first multi-channel bidirectional analog switch U3 is preferably an 8-channel bidirectional analog switch of model CD74HC4051; the control module 4 in this embodiment is preferably an MCU controller U1 of model ML51EB9AE. The first enable port of the first multi-channel bidirectional analog switch U3 is the EN port; the multiple first select ports of the first multi-channel bidirectional analog switch U3 include three select ports: S0, S1, and S2; the EN port and the three select ports S0, S1, and S2 of the first multi-channel bidirectional analog switch U3 are respectively connected to the MCU controller U1 of the control module 4 through electrical networks R_EN0, R_S0, R_S1, and R_S2.

[0031] More detailed, such as Figure 2 , Figure 4 and Figure 7 As shown, the CH0~CH7 ports of the first multi-channel bidirectional analog switch U3 are eight bidirectional input / output ports, and the CH0~CH7 ports are respectively connected to the receiving circuit 102. The COM port of the first multi-channel bidirectional analog switch U3 is a common terminal, and the COM port is connected to the amplification and comparison module 3 through the electrical network DPA_IN. The control module 4 can select one of the CH0~CH7 ports by controlling the three selection ports S0, S1, and S2 and the enable port EN of the first multi-channel bidirectional analog switch U3. The detection signal received by the corresponding phototransistors Q1~Q8 is sent to the amplification and comparison module 3. Thus, it can be seen that the detection signal reception of the eight-channel receiving circuit 102 can be realized through four ports.

[0032] like Figure 4 and Figure 5 As shown, in this embodiment, the number of the first multi-channel bidirectional analog switches is three (U3, U31, and U32), and the preferred model is CD74HC4051. U3, U31, and U32 are connected in parallel through the first selection ports S0, S1, and S2, and then connected to the MCU controller U1 of the control module 4 through electrical networks R_S0, R_S1, and R_S2, respectively. The first enable ports EN of U3, U31, and U32 are connected to the MCU controller U1 of the control module 4 through electrical networks R_EN0, R_EN1, and R_EN2, respectively.

[0033] It is worth noting that in this embodiment, U3, U31, and U32 can connect to a maximum of 24 receiving circuits 102. The control module 4 can realize the reception of detection signals from 24 receiving circuits 102 by controlling the three selection ports S0, S1, and S2 and the three enable ports EN of U3, U31, and U32 connected in parallel, totaling six ports. When the circuit uses a larger number of first multi-channel bidirectional analog switches, it can be expanded to receive detection signals from more receiving circuits 102, thus saving more hardware costs.

[0034] like Figure 3 and Figure 4 As shown, in this embodiment, the second multi-channel bidirectional analog switch U2 preferably uses an 8-channel bidirectional analog switch of model CD74HC4051. The second enable port of the second multi-channel bidirectional analog switch U2 is the EN port; the multiple second select ports of the second multi-channel bidirectional analog switch U2 include three select ports: S0, S1, and S2; the EN port and the three select ports S0, S1, and S2 of the second multi-channel bidirectional analog switch U2 are respectively connected to the MCU controller U1 of the control module 4 through electrical networks S_EN0, S_S0, S_S1, and S_S2.

[0035] More detailed, such as Figure 3 and Figure 4 As shown, the CH0~CH7 ports of the second multi-channel bidirectional analog switch U2 are 8-channel bidirectional input / output ports, and the CH0~CH7 ports are respectively connected to the transmitting circuit 202; the COM port of the second multi-channel bidirectional analog switch U2 is the common terminal, and the COM port is grounded through resistor R33; the control module 4 can control the three selection ports S0, S1 and S2 and the enable port EN of the second multi-channel bidirectional analog switch U2 to select one of the COM port and CH0~CH7 ports to be grounded through resistor R33, and the corresponding light-emitting diodes D1~D8 will emit detection signals. Therefore, it can be seen that the detection signals of the 8-channel transmitting circuit 202 can be emitted through 4 ports.

[0036] like Figure 4 and Figure 6 As shown, in this embodiment, the number of the second multi-channel bidirectional analog switches is three (U2, U21, and U22), and the preferred model is CD74HC4051. U2, U21, and U22 are connected in parallel through the second selection ports S0, S1, and S2, and then connected to the MCU controller U1 of the control module 4 through electrical networks S_S0, S_S1, and S_S2, respectively. The second enable ports EN of U2, U21, and U22 are connected to the control module 4 through electrical networks S_EN0, S_EN1, and S_EN2, respectively.

[0037] It is worth noting that in this embodiment, U2, U21, and U22 can connect to a maximum of 24 transmitting circuits 202. The control module 4 can receive detection signals from all 24 transmitting circuits 202 by controlling three parallel selection ports S0, S1, and S2 and three enable ports EN of U2, U21, and U22, totaling six ports. When the circuit uses a larger number of second-channel bidirectional analog switches, it can expand to transmit more detection signals from the transmitting circuits 202, thus saving more hardware costs.

[0038] Therefore, compared with the existing technology, when a larger number of SMT trays need to be inspected, the detection circuit structure provided by this utility model is simpler, more scalable, requires fewer hardware resources, and is less expensive.

[0039] like Figure 2 and Figure 7 As shown, the amplification unit 301 includes a multi-stage amplification circuit 3011 and a DC blocking capacitor C10; one end of the DC blocking capacitor C10 is connected to the receiving switch unit 101 through the electrical network DPA_IN, and the other end of the DC blocking capacitor C10 is connected to the multi-stage amplification circuit 3011.

[0040] It is particularly important to note that the two ends of the DC blocking capacitor C10 are connected to the multi-stage amplifier circuit 3011 and the receiving switch unit 101, respectively. This is because if the signal emitted from the receiving switch unit 101 is a DC signal, it cannot pass through the DC blocking capacitor C10 and enter the multi-stage amplifier circuit 3011. If the signal emitted from the receiving switch unit 101 is a pulse signal, it can pass through the DC blocking capacitor C10 and enter the multi-stage amplifier circuit 3011. In the multi-stage amplifier circuit 3011, the adjustable resistor R36 is connected in parallel across the resistor R35. This adjustable resistor R36 can be used to change the amplification factor of the amplifier circuit 301 according to actual conditions and needs, thereby meeting different application requirements and improving the flexibility of the detection circuit.

[0041] like Figure 8As shown, when the transmitter 7 and receiver 8 adopt a reflective layout, when the SMT tray position 6 is empty, the transmitted signal is isolated and blocked by the isolation block 9 and absorbed by the signal absorption plate 10. The transmitted signal from the transmitter 7 cannot reach the receiver 8. Therefore, the signal received from the receiving switch unit 101 remains unchanged and is a DC signal, thus it cannot pass through the DC blocking capacitor C10. The transmitter 7 refers to the light-emitting diodes D1~D8 in the transmitting circuit 202; the receiver 8 refers to the phototransistors Q1~Q8 in the receiving circuit 102. The isolation block 9 refers to the baffle structure between the transmitter 7 and the receiver 8 used to block and isolate the transmitted signal. The signal absorption plate 10 refers to the light-absorbing plate on one side of the transmitter 7 and the receiver 8 used to absorb the transmitted signal when there is no tray 5 in the SMT tray position 6. The transmitter 7, receiver 8, isolation block 9, and signal absorption plate 10 are all mounted on the circuit board 11 of the SMT tray detection circuit. The tray 5 refers to the SMT tray, including but not limited to high-transparency trays. SMT tray position 6 refers to the inspection slot of tray 5.

[0042] like Figure 8 As shown, when there is a tray 5 in SMT tray position 6, including a tray 5 with high transparency, the signal emitted by the transmitter 7 is reflected by the tray 5, and the signal received by the receiving switch unit 101 is a pulse signal, which can enter the multi-stage amplifier circuit 3011 through the DC blocking capacitor C10.

[0043] In this embodiment, the multi-stage amplifier circuit 3011 adopts the following... Figure 7 The two-stage amplifier circuit shown; the multi-stage amplifier circuit 3011 amplifies the received signal and sends it to the comparison unit 302. The reason for using a two-stage amplifier circuit is to ensure that the detection signal received from the receiving switch unit 101 is amplified, especially when the SMT tray position 6 is set to a high transparency tray, the detection signal can be amplified to a reasonable detectable value.

[0044] like Figure 4 and Figure 7 As shown, the comparison unit 302 includes a comparator U6, a reference voltage source DC5V, an adjustable potentiometer R37, a first voltage divider resistor R13, and a second voltage divider resistor R15. One end of the first voltage divider resistor R13 is connected to the reference voltage source DC5V, and the other end of the first voltage divider resistor R13 is connected to the non-inverting input of the comparator U6 and one end of the adjustable potentiometer R37, respectively. The other end of the adjustable potentiometer R37 is grounded through the second voltage divider resistor R15. The inverting input of the comparator U6 is connected to the amplification unit 301. The output of the comparator U6 is connected to the control module 4.

[0045] More specifically, the amplified signal DPA_OUT from the aforementioned multi-stage amplification circuit 3011 enters the inverting input of comparator U6. The input voltage of the non-inverting input of comparator U6 can be adjusted by the adjustable potentiometer R37. By adjusting the resistance of the adjustable potentiometer R37, the threshold comparison voltage of the non-inverting input of comparator U6 can be set, allowing the detection signal from the high-transparency tray to be detected. The output of comparator U6 is connected to the MCU controller U1 of the control module 4 via the electrical network DPA_Sig. It should be noted that, unlike existing technologies that use high-precision ADCs to detect inspection signals, this embodiment uses a simpler amplification and comparison circuit, resulting in a superior circuit structure and lower cost for detecting high-transparency trays.

[0046] In summary, this embodiment provides an SMT reel detection circuit, which provides a hardware circuit foundation for solving the detection of a large number of SMT reels. In particular, the detection circuit structure is better for high transparency reels. The circuit structure of this embodiment is simple, has good scalability, requires less hardware resources, and is more cost-effective.

[0047] The specific embodiments described above are preferred embodiments of this utility model, and are not intended to limit the specific scope of this utility model. The scope of this utility model includes, but is not limited to, these specific embodiments. All equivalent changes made in accordance with the shape and structure of this utility model are within the protection scope of this utility model.

Claims

1. An SMT tray detection circuit, characterized in that, include: The system comprises a receiving module, a transmitting module, an amplification and comparison module, and a control module. The receiving module includes a receiving switch unit and multiple receiving circuits, each connected to the receiving switch unit, which is also connected to the amplification and comparison module and the control module. The transmitting module includes a transmitting switch unit and multiple transmitting circuits, each connected to the transmitting switch unit, which is also connected to the control module. The amplification and comparison module includes an amplification unit and a comparison unit, the amplification unit being connected to the receiving switch unit, and the comparison unit being connected to both the amplification unit and the control module.

2. The SMT tray detection circuit according to claim 1, characterized in that, The number of receiving circuits is equal to the number of transmitting circuits, and there is a one-to-one correspondence between the receiving circuits and the transmitting circuits.

3. The SMT tray detection circuit according to claim 2, characterized in that, The receiving switch unit includes a first multi-channel bidirectional analog switch, which is connected to the receiving circuit; the transmitting switch unit includes a second multi-channel bidirectional analog switch, which is connected to the transmitting circuit.

4. The SMT tray detection circuit according to claim 3, characterized in that, The first multi-channel bidirectional analog switch includes a first enable port and multiple first gating ports; the first enable port and multiple first gating ports are connected to the control module.

5. The SMT tray detection circuit according to claim 4, characterized in that, The number of the first multi-channel bidirectional analog switches is multiple; the multiple first multi-channel bidirectional analog switches are connected in parallel with each other through the first gating port and then connected to the control module; the first enable ports of the multiple first multi-channel bidirectional analog switches are respectively connected to the control module.

6. The SMT tray detection circuit according to claim 3, characterized in that, The second multi-channel bidirectional analog switch includes a second enable port and multiple second gating ports; the second enable port and multiple second gating ports are connected to the control module.

7. The SMT tray detection circuit according to claim 6, characterized in that, The number of the second multiplex analog switches is multiple; the multiple second multiplex bidirectional analog switches are connected in parallel to each other through the second gating port and then connected to the control module; the second enable ports of the multiple second multiplex analog switches are respectively connected to the control module.

8. The SMT tray detection circuit according to any one of claims 1 to 7, wherein the amplification unit includes a multi-stage amplification circuit and a DC blocking capacitor; one end of the DC blocking capacitor is connected to the receiving switch unit, and the other end of the DC blocking capacitor is connected to the multi-stage amplification circuit.

9. The SMT tray detection circuit according to claim 8, characterized in that, The comparison unit includes a comparator, an adjustable potentiometer, a reference voltage source, a first voltage divider resistor, and a second voltage divider resistor. One end of the first voltage divider resistor is connected to the reference voltage source, and the other end of the first voltage divider resistor is connected to the non-inverting input of the comparator and one end of the adjustable potentiometer, respectively. The other end of the adjustable potentiometer is grounded through the second voltage divider resistor. The inverting input of the comparator is connected to the amplification unit. The output of the comparator is connected to the control module.

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