CN215682316U - RS-485 communication activation circuit - Google Patents
RS-485 communication activation circuit Download PDFInfo
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- CN215682316U CN215682316U CN202121756876.0U CN202121756876U CN215682316U CN 215682316 U CN215682316 U CN 215682316U CN 202121756876 U CN202121756876 U CN 202121756876U CN 215682316 U CN215682316 U CN 215682316U
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Abstract
The utility model discloses an RS-485 communication activation circuit, which comprises a micro control unit, a 485 communication module and a first optocoupler module, wherein: the micro control unit is in bidirectional communication connection with the 485 communication module, and the 485 communication module is in bidirectional communication connection with an external equipment end; the micro control unit is in two-way communication connection with the first optical coupling module, the first optical coupling module is in communication connection with an external device end, and the first optical coupling module is used for carrying out communication activation on the micro control unit after receiving a signal of the external device end. The communication activation circuit of the 485 communication circuit has the advantages of strong anti-interference capability and high safety performance, and allows the 485 communication circuit to enter a sleep mode when no communication exists, and the 485 communication circuit 485A, B voltage changes to activate the system when a communication signal exists, so that the power consumption and the sleep are not influenced.
Description
Technical Field
The utility model relates to the technical field of communication, in particular to an RS-485 communication activation circuit.
Background
The RS-485 has wide application in a multipoint communication system, and the traditional RS-485 communication circuit can only carry out simple communication, can influence the data transmission under the environment of strong interference and large current, and even can burn out chips and connected equipment. At the same time, in certain very demanding endurance environments, the device needs to maintain ultra-low power consumption in certain modes. However, it is a difficult point that the 485 communication system needs to achieve both real-time communication and ultra-low power consumption.
Chinese patent publication No. CN203933593U, publication No. 11/05/2014, discloses a half-duplex RS-485 isolation communication circuit, which includes: the device comprises a first RS-485 receiving and transmitting module, a second RS-485 receiving and transmitting module and an isolation control module, wherein the first RS-485 receiving and transmitting module is used for realizing conversion between an RS-485 signal and an RS-232 signal, the second RS-485 receiving and transmitting module is used for realizing signal conversion which is opposite to the signal conversion carried out by the first RS-485 receiving and transmitting module, and the isolation control module is connected between the first RS-485 receiving and transmitting module and the second RS-485 receiving and transmitting module so as to control the receiving and transmitting states of the first RS-485 receiving and transmitting module and the second RS-485 receiving and transmitting module and carry out isolation transmission on the signals of the first RS-485 receiving and transmitting module and the second RS-485 receiving and transmitting module. The patent can not keep ultra-low power consumption and simultaneously realizes real-time communication.
SUMMERY OF THE UTILITY MODEL
The utility model provides an RS-485 communication activation circuit which can realize real-time communication while keeping ultralow power consumption.
In order to solve the technical problems, the technical scheme of the utility model is as follows:
the utility model provides a RS-485 communication activation circuit, includes little the control unit, 485 communication module, first opto-coupler module, wherein:
the micro control unit is in bidirectional communication connection with the 485 communication module, and the 485 communication module is in bidirectional communication connection with an external equipment end;
the micro control unit is in two-way communication connection with the first optical coupling module, the first optical coupling module is in communication connection with an external device end, and the first optical coupling module is used for carrying out communication activation on the micro control unit after receiving a signal of the external device end.
Preferably, the first optical coupling module comprises a first optical coupling isolation chip U7, a resistor R75, a resistor R89, a capacitor C65 and a diode D20, wherein:
the anode of the diode D20 is electrically connected with an external device end, the cathode of the diode D20 is electrically connected with one end of a resistor R89, the other end of the resistor R89 is electrically connected with one end of a capacitor C65 and a first input end of a first optical coupling isolation chip U7, and the first input end of the first optical coupling isolation chip U7 is electrically connected with the external device end and the other end of the capacitor C65;
a first output end of the first optical coupling isolation chip U7 is electrically connected with one end of a resistor R75, and the other end of the resistor R75 is electrically connected with a DC _ S end of the micro control unit.
Preferably, the optical coupler further comprises a digital isolation module, a power isolation module and a second optical coupling module, wherein:
the micro control unit is in bidirectional communication connection with the digital isolation module and the second optical coupling module respectively, is connected with the power isolation module, is in bidirectional communication connection with the 485 communication module through the digital isolation module and the second optical coupling module, and sends or receives signals;
the digital isolation module is connected with the power isolation module, the digital isolation module is in bidirectional communication connection with the 485 communication module, and the digital isolation module is used for digital isolation;
the second optical coupling module is in bidirectional communication connection with the 485 communication module;
the power isolation module is further connected with the 485 communication module and used for power isolation.
Preferably, the power isolation module comprises a power isolation chip U5, an electrode capacitor C33, a capacitor C34, an electrode capacitor C35, a capacitor C37, an electrode capacitor C50, an electrode capacitor C53 and a resistor R67, wherein:
the anode of the electrode capacitor C33 is electrically connected with an external power supply, one end of a capacitor C34 and one end of a resistor R67 respectively, and the cathode of the electrode capacitor C33 is electrically connected with the other end of a capacitor C34, the cathode of an electrode capacitor C35, one end of a capacitor C37, the cathode of an electrode capacitor C53 and the Vin-end of a power isolation chip U5 respectively;
the other end of the resistor R67 is respectively and electrically connected with the anode of the electrode capacitor C35, the other end of the capacitor C37 and the Vin + end of the power isolation chip U5;
the positive electrode of the electrode capacitor C50 is electrically connected with the positive electrode of the electrode capacitor C53, and the negative electrode of the electrode capacitor C53 is electrically connected with the Vout-end of the power isolation chip U5;
and the Vout + end and the Vout-end of the power isolation chip U5 are second outputs of the power isolation module.
Preferably, the power isolation module further includes a buck chip U9, an electrode capacitor C67, a capacitor C68, an electrode capacitor C77, a capacitor C78, a resistor R97, and a light emitting diode D1, wherein:
the Vin end of the voltage-reducing chip U9 is respectively and electrically connected with the Vout + end of the power isolation chip U5, the anode of the electrode capacitor C67 and one end of the capacitor C68, the Vout end of the voltage-reducing chip U9 is respectively and electrically connected with the anode of the electrode capacitor C77, one end of the capacitor C78 and one end of the resistor R97, the Vout end of the voltage-reducing chip U9 is used as the second output of the power isolation module, and the GND end of the voltage-reducing chip U9 is grounded;
the negative electrode of the electrode capacitor C67, the other end of the capacitor C68, the negative electrode of the electrode capacitor C77 and the other end of the capacitor C78 are all grounded;
the other end of the resistor R97 is electrically connected with the anode of the light emitting diode D1, and the cathode of the light emitting diode D1 is grounded.
Preferably, the digital isolation module comprises a digital isolation chip U8, a resistor R77, a resistor R76, a resistor R87, a resistor R86, a resistor R66, a resistor R69, a resistor R74, a resistor R78, a capacitor C51, a capacitor C52, a capacitor C54, a capacitor C64, a field effect transistor M3 and a field effect transistor M4, wherein:
the A1 end of the digital isolation chip U8 is electrically connected with the 485TX end of the micro control unit through the resistor R77, the 485TX end of the micro control unit is also electrically connected with one end of a capacitor C51, the 485RX end of the micro control unit is also electrically connected with one end of a capacitor C52, the A2 end of the digital isolation chip U8 is electrically connected with the 485RX end of the micro control unit through the resistor R76, the B1 end of the digital isolation chip U8 is electrically connected with the 485 communication module through the resistor R87, the B2 end of the digital isolation chip U8 is electrically connected with the 485 communication module through the resistor R86, and the VDD1 end and the VDD2 end of the digital isolation chip U8 are connected with a power supply;
one end of the resistor R66 is connected with an SCK clock signal, the other end of the resistor R66 is respectively and electrically connected with one end of the resistor R69 and the gate of the field-effect tube M3, the drain of the field-effect tube M3 is electrically connected with one end of the resistor R74, the other end of the resistor R74 is respectively and electrically connected with one end of the resistor R78 and the gate of the field-effect tube M4, the source of the field-effect tube M4 is respectively and electrically connected with one end of the capacitor C54 and the VDD1 end of the digital isolation chip U8, and the VDD2 end of the digital isolation chip U8 is electrically connected with one end of the capacitor C64;
the other end of the resistor R69, the source of the field effect transistor M3, the other end of the resistor R78, the drain of the field effect transistor M4, the other end of the capacitor C54, the other end of the capacitor C64, the other end of the capacitor C51 and the other end of the capacitor C52 are all grounded.
Preferably, the second optical coupling module comprises a second optical coupling isolation chip U6, a resistor R70, a resistor R84 and a capacitor C39, wherein:
one end of the resistor R70 is electrically connected with the 485REM end of the micro control unit, and the other end of the resistor R70 is electrically connected with the second input end of the second optical coupling isolation chip U6 and one end of the capacitor C39 respectively;
a second output end of the second optical coupling isolation chip U6 is connected with a power supply, and a second output end of the second optical coupling isolation chip U6 is electrically connected with the 485 communication module and one end of the resistor R84 respectively;
and a second input end of the second optical coupling isolation chip U6, the other end of the capacitor C39 and the other end of the resistor R84 are all grounded.
Preferably, the 485 communication module includes a 485 communication chip U4, a resistor R68, a resistor R93, a resistor R92, an inductor L3, an inductor L2, a capacitor C75, a capacitor C76, an electrode capacitor C69, an electrode capacitor C61, a zener diode D15, and a zener diode D14, wherein:
the RO end of the 485 communication chip U4 is electrically connected with the B2 end of the digital isolation chip U8, the DI end of the 485 communication chip U4 is electrically connected with the B1 end of the digital isolation chip U8, the DE end of the 485 communication chip U4 is electrically connected with the second output end of the second optical coupling isolation chip U6 through the resistor R68, the B end of the 485 communication chip U4 is electrically connected with one end of the resistor R93, and the A end of the 485 communication chip U4 is electrically connected with one end of the resistor R92;
the other end of the resistor R93 is electrically connected with one end of an inductor L3, and the other end of the inductor L3 is electrically connected with one end of a capacitor C76, the negative electrode of a voltage stabilizing diode D15 and an external equipment end respectively;
the other end of the resistor R92 is electrically connected with one end of an inductor L2, and the other end of the inductor L2 is electrically connected with one end of a capacitor C75, the negative electrode of a voltage stabilizing diode D14 and an external equipment end respectively;
the other end of the capacitor C76, the anode of the voltage stabilizing diode D15, the other end of the capacitor C75 and the anode of the voltage stabilizing diode D14 are all grounded;
the anode of the voltage-stabilizing diode D15 is also electrically connected with the cathode of the electrode capacitor C69, the anode of the electrode capacitor C69 is electrically connected with the anode of the electrode capacitor C61, and the cathode of the electrode capacitor C61 is connected with an ESD ground wire.
Preferably, the 485 communication module further comprises a resistor R81, a resistor R80, a capacitor C62 and a capacitor C63, wherein:
the VCC end of 485 communication chip U4 is connected with power, resistance R81's one end, electric capacity C62's one end, electric capacity C63's one end electricity respectively, 485 communication chip U4's GND end and resistance R80's one end are all grounded, resistance R80's the other end and 485 communication chip U4's B termination electricity are connected, R81's the other end and 485 communication chip U4's A termination electricity are connected, electric capacity C62's the other end, electric capacity C63's the other end is all grounded.
Preferably, the digital isolation chip U8 adopts a SI8421AB-D-ISR chip, and the power isolation chip U5 adopts a B1209S-1WR3 chip.
Compared with the prior art, the technical scheme of the utility model has the beneficial effects that:
the communication activation circuit of the 485 communication circuit has the advantages of strong anti-interference capability and high safety performance, and allows the 485 communication circuit to enter a sleep mode when no communication exists, and the 485 communication circuit 485A, B voltage changes to activate the system when a communication signal exists, so that the power consumption and the sleep are not influenced.
Drawings
Fig. 1 is a schematic diagram of a circuit module according to the present invention.
Fig. 2 is a schematic structural diagram of a first optical coupler module according to the present invention.
FIG. 3 is a schematic diagram of a power isolation module according to the present invention.
FIG. 4 is a schematic diagram of the digital isolation module structure according to the present invention.
Fig. 5 is a schematic structural diagram of a second optical coupling module according to the present invention.
Fig. 6 is a schematic structural diagram of a 485 communication module according to the present invention.
Detailed Description
The drawings are for illustrative purposes only and are not to be construed as limiting the patent;
for the purpose of better illustrating the embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product;
it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
The technical solution of the present invention is further described below with reference to the accompanying drawings and examples.
Example 1
This embodiment provides an RS-485 communication activation circuit, as shown in fig. 1, including little the control unit, 485 communication module, first opto-coupler module, wherein:
the micro control unit is in bidirectional communication connection with the 485 communication module, and the 485 communication module is in bidirectional communication connection with an external equipment end;
the micro control unit is in two-way communication connection with the first optical coupling module, the first optical coupling module is in communication connection with an external device end, and the first optical coupling module is used for carrying out communication activation on the micro control unit after receiving a signal of the external device end.
The first optical coupling module is shown in fig. 2, and includes a first optical coupling isolation chip U7, a resistor R75, a resistor R89, a capacitor C65, and a diode D20, where:
the anode of the diode D20 is electrically connected with an external device end, the cathode of the diode D20 is electrically connected with one end of a resistor R89, the other end of the resistor R89 is electrically connected with one end of a capacitor C65 and a first input end of a first optical coupling isolation chip U7, and the first input end of the first optical coupling isolation chip U7 is electrically connected with the external device end and the other end of the capacitor C65;
a first output end of the first optical coupling isolation chip U7 is electrically connected with one end of a resistor R75, and the other end of the resistor R75 is electrically connected with a DC _ S end of the micro control unit.
Still include digital isolation module and power isolation module and second opto-coupler module, wherein:
the micro control unit is in bidirectional communication connection with the digital isolation module and the second optical coupling module respectively, is connected with the power isolation module, is in bidirectional communication connection with the 485 communication module through the digital isolation module and the second optical coupling module, and sends or receives signals;
the digital isolation module is connected with the power isolation module, the digital isolation module is in bidirectional communication connection with the 485 communication module, and the digital isolation module is used for digital isolation;
the second optical coupling module is in bidirectional communication connection with the 485 communication module;
the power isolation module is further connected with the 485 communication module and used for power isolation.
The power isolation module is shown in fig. 3, and includes a power isolation chip U5, an electrode capacitor C33, a capacitor C34, an electrode capacitor C35, a capacitor C37, an electrode capacitor C50, an electrode capacitor C53, and a resistor R67, where:
the anode of the electrode capacitor C33 is electrically connected with an external power supply, one end of a capacitor C34 and one end of a resistor R67 respectively, and the cathode of the electrode capacitor C33 is electrically connected with the other end of a capacitor C34, the cathode of an electrode capacitor C35, one end of a capacitor C37, the cathode of an electrode capacitor C53 and the Vin-end of a power isolation chip U5 respectively;
the other end of the resistor R67 is respectively and electrically connected with the anode of the electrode capacitor C35, the other end of the capacitor C37 and the Vin + end of the power isolation chip U5;
the positive electrode of the electrode capacitor C50 is electrically connected with the positive electrode of the electrode capacitor C53, and the negative electrode of the electrode capacitor C53 is electrically connected with the Vout-end of the power isolation chip U5;
the Vout + terminal and the Vout-terminal of the power isolation chip U5 are the first output of the power isolation module.
The power isolation module further comprises a voltage reduction chip U9, an electrode capacitor C67, a capacitor C68, an electrode capacitor C77, a capacitor C78, a resistor R97 and a light emitting diode D1, wherein:
the Vin end of the voltage-reducing chip U9 is respectively and electrically connected with the Vout + end of the power isolation chip U5, the anode of the electrode capacitor C67 and one end of the capacitor C68, the Vout end of the voltage-reducing chip U9 is respectively and electrically connected with the anode of the electrode capacitor C77, one end of the capacitor C78 and one end of the resistor R97, the Vout end of the voltage-reducing chip U9 is used as the second output of the power isolation module, and the GND end of the voltage-reducing chip U9 is grounded;
the negative electrode of the electrode capacitor C67, the other end of the capacitor C68, the negative electrode of the electrode capacitor C77 and the other end of the capacitor C78 are all grounded;
the other end of the resistor R97 is electrically connected with the anode of the light emitting diode D1, and the cathode of the light emitting diode D1 is grounded.
As shown in fig. 4, the digital isolation module includes a digital isolation chip U8, a resistor R77, a resistor R76, a resistor R87, a resistor R86, a resistor R66, a resistor R69, a resistor R74, a resistor R78, a capacitor C51, a capacitor C52, a capacitor C54, a capacitor C64, a field effect transistor M3, and a field effect transistor M4, where:
the A1 end of the digital isolation chip U8 is electrically connected with the 485TX end of the micro control unit through the resistor R77, the 485TX end of the micro control unit is also electrically connected with one end of a capacitor C51, the 485RX end of the micro control unit is also electrically connected with one end of a capacitor C52, the A2 end of the digital isolation chip U8 is electrically connected with the 485RX end of the micro control unit through the resistor R76, the B1 end of the digital isolation chip U8 is electrically connected with the 485 communication module through the resistor R87, the B2 end of the digital isolation chip U8 is electrically connected with the 485 communication module through the resistor R86, and the VDD1 end and the VDD2 end of the digital isolation chip U8 are connected with a power supply;
one end of the resistor R66 is connected with an SCK clock signal, the other end of the resistor R66 is respectively and electrically connected with one end of the resistor R69 and the gate of the field-effect tube M3, the drain of the field-effect tube M3 is electrically connected with one end of the resistor R74, the other end of the resistor R74 is respectively and electrically connected with one end of the resistor R78 and the gate of the field-effect tube M4, the source of the field-effect tube M4 is respectively and electrically connected with one end of the capacitor C54 and the VDD1 end of the digital isolation chip U8, and the VDD2 end of the digital isolation chip U8 is electrically connected with one end of the capacitor C64;
the other end of the resistor R69, the source of the field effect transistor M3, the other end of the resistor R78, the drain of the field effect transistor M4, the other end of the capacitor C54, the other end of the capacitor C64, the other end of the capacitor C51 and the other end of the capacitor C52 are all grounded.
The second optical coupling module is shown in fig. 5, and includes a second optical coupling isolation chip U6, a resistor R70, a resistor R84, and a capacitor C39, where:
one end of the resistor R70 is electrically connected with the 485REM end of the micro control unit, and the other end of the resistor R70 is electrically connected with the second input end of the second optical coupling isolation chip U6 and one end of the capacitor C39 respectively;
a second output end of the second optical coupling isolation chip U6 is connected with a power supply, and a second output end of the second optical coupling isolation chip U6 is electrically connected with the 485 communication module and one end of the resistor R84 respectively;
and a second input end of the second optical coupling isolation chip U6, the other end of the capacitor C39 and the other end of the resistor R84 are all grounded.
As shown in fig. 6, the 485 communication module includes a 485 communication chip U4, a resistor R68, a resistor R93, a resistor R92, an inductor L3, an inductor L2, a capacitor C75, a capacitor C76, an electrode capacitor C69, an electrode capacitor C61, a zener diode D15, and a zener diode D14, where:
the RO end of the 485 communication chip U4 is electrically connected with the B2 end of the digital isolation chip U8, the DI end of the 485 communication chip U4 is electrically connected with the B1 end of the digital isolation chip U8, the DE end of the 485 communication chip U4 is electrically connected with the second output end of the first optical coupling isolation chip U6 through the resistor R68, the B end of the 485 communication chip U4 is electrically connected with one end of the resistor R93, and the A end of the 485 communication chip U4 is electrically connected with one end of the resistor R92;
the other end of the resistor R93 is electrically connected with one end of an inductor L3, and the other end of the inductor L3 is electrically connected with one end of a capacitor C76, the negative electrode of a voltage stabilizing diode D15 and an external equipment end respectively;
the other end of the resistor R92 is electrically connected with one end of an inductor L2, and the other end of the inductor L2 is electrically connected with one end of a capacitor C75, the negative electrode of a voltage stabilizing diode D14 and an external equipment end respectively;
the other end of the capacitor C76, the anode of the voltage stabilizing diode D15, the other end of the capacitor C75 and the anode of the voltage stabilizing diode D14 are all grounded;
the anode of the voltage-stabilizing diode D15 is also electrically connected with the cathode of the electrode capacitor C69, the anode of the electrode capacitor C69 is electrically connected with the anode of the electrode capacitor C61, and the cathode of the electrode capacitor C61 is connected with an ESD ground wire.
The 485 communication module further comprises a resistor R81, a resistor R80, a capacitor C62 and a capacitor C63, wherein:
the VCC end of 485 communication chip U4 is connected with power, resistance R81's one end, electric capacity C62's one end, electric capacity C63's one end electricity respectively, 485 communication chip U4's GND end and resistance R80's one end are all grounded, resistance R80's the other end and 485 communication chip U4's B termination electricity are connected, R81's the other end and 485 communication chip U4's A termination electricity are connected, electric capacity C62's the other end, electric capacity C63's the other end is all grounded.
The digital isolation chip U8 adopts an SI8421AB-D-ISR chip, and the power isolation chip U5 adopts a B1209S-1WR3 chip.
The specific implementation process is given as follows:
communication activation working principle: the system enters low power consumption, the micro-processing unit can enter an ultra-low power consumption mode through sending signals, in the ultra-low power consumption mode, the port A of the 485 communication chip is pulled up through the resistor R81, the port B of the 485 communication chip is pulled down through the resistor R80, the first optical coupling isolation chip U7 is cut off, no signal is input to the DC _ S pin of the micro-processing unit, and the system is kept in the ultra-low power consumption mode. When the 485 bus is in communication, the capacitor C65 is charged through the port B of the 485 communication chip, the diode D20 and the resistor R89, the first optocoupler isolation chip U7 is conducted, the high level is input to the DC _ S end of the microprocessing chip, the system quits ultra-low power consumption, and the system enters a normal working mode. The system can keep real-time communication in the ultra-low power consumption mode.
The micro-processing unit sends signals to the equipment end: before sending data, the 485REM port of the microprocessing unit sends a high level firstly, the resistance R70 is used for sending a second optical coupling isolation chip U6, the second optical coupling isolation chip U6 is conducted, the DE pin outputs 5V, the resistance R68 is used for sending the DE pin of the 485 communication chip U4, and the 485 communication chip U4 marks the 485 entering sending mode. At the moment, the microprocessing unit sends data through the TX port, the data is sent to the digital isolation chip U8 through the resistor R77, the isolation TX data is output from the B1 pin of the microprocessing unit and is sent to the DI pin of the 485 chip through the resistor R87, the serial port signal is converted into a 485 differential signal by the 485 chip U4 and is sent to a device end, and the signal sending process is completed.
The device sends a signal to the micro-processing unit: before sending data, the 485REM mouth of microprocessing unit can send a low level earlier, gives second opto-coupler isolation chip U6 through resistance R70, and second opto-coupler isolation chip U6 opto-coupler is cut off, and the DE defaults to pull down 0V, gives the DE foot to 485 communication chip U4 through resistance R68, marks 485 entering receiving mode. At the moment, 485 differential data of the equipment is sent to an AB pin of a 485 communication chip U4 through an inductor L3, a resistor R93, an inductor L2 and a resistor R92, the 485 communication chip converts 485 differential signals into TTL levels and sends the TTL levels to a digital isolation chip U8 from an RO pin and a resistor R86, isolation RX data is output from an A2 pin of the 485 communication chip, and the isolation RX data is transmitted to a micro-processing unit through a resistor R76, so that the signal receiving process is completed.
The same or similar reference numerals correspond to the same or similar parts;
the terms describing positional relationships in the drawings are for illustrative purposes only and are not to be construed as limiting the patent;
it should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.
Claims (10)
1. The utility model provides a RS-485 communication activation circuit which characterized in that, includes little the control unit, 485 communication module, first opto-coupler module, wherein:
the micro control unit is in bidirectional communication connection with the 485 communication module, and the 485 communication module is in bidirectional communication connection with an external equipment end;
the micro control unit is in two-way communication connection with the first optical coupling module, the first optical coupling module is in communication connection with an external device end, and the first optical coupling module is used for carrying out communication activation on the micro control unit after receiving a signal of the external device end.
2. The RS-485 communication activation circuit of claim 1, wherein the first optical coupling module comprises a first optical coupling isolation chip U7, a resistor R75, a resistor R89, a capacitor C65 and a diode D20, wherein:
the anode of the diode D20 is electrically connected with an external device end, the cathode of the diode D20 is electrically connected with one end of a resistor R89, the other end of the resistor R89 is electrically connected with one end of a capacitor C65 and a first input end of a first optical coupling isolation chip U7, and the first input end of the first optical coupling isolation chip U7 is electrically connected with the external device end and the other end of the capacitor C65;
a first output end of the first optical coupling isolation chip U7 is electrically connected with one end of a resistor R75, and the other end of the resistor R75 is electrically connected with a DC _ S end of the micro control unit.
3. The RS-485 communication activation circuit of claim 2, further comprising a digital isolation module and a power isolation module and a second optocoupler module, wherein:
the micro control unit is in bidirectional communication connection with the digital isolation module and the second optical coupling module respectively, is connected with the power isolation module, is in bidirectional communication connection with the 485 communication module through the digital isolation module and the second optical coupling module, and sends or receives signals;
the digital isolation module is connected with the power isolation module, the digital isolation module is in bidirectional communication connection with the 485 communication module, and the digital isolation module is used for digital isolation;
the second optical coupling module is in bidirectional communication connection with the 485 communication module;
the power isolation module is further connected with the 485 communication module and used for power isolation.
4. The RS-485 communication activation circuit according to claim 3, wherein the power isolation module comprises a power isolation chip U5, an electrode capacitor C33, a capacitor C34, an electrode capacitor C35, a capacitor C37, an electrode capacitor C50, an electrode capacitor C53 and a resistor R67, wherein:
the anode of the electrode capacitor C33 is electrically connected with an external power supply, one end of a capacitor C34 and one end of a resistor R67 respectively, and the cathode of the electrode capacitor C33 is electrically connected with the other end of a capacitor C34, the cathode of an electrode capacitor C35, one end of a capacitor C37, the cathode of an electrode capacitor C53 and the Vin-end of a power isolation chip U5 respectively;
the other end of the resistor R67 is respectively and electrically connected with the anode of the electrode capacitor C35, the other end of the capacitor C37 and the Vin + end of the power isolation chip U5;
the positive electrode of the electrode capacitor C50 is electrically connected with the positive electrode of the electrode capacitor C53, and the negative electrode of the electrode capacitor C53 is electrically connected with the Vout-end of the power isolation chip U5;
and the Vout + end and the Vout-end of the power isolation chip U5 are second outputs of the power isolation module.
5. The RS-485 communication activation circuit according to claim 4, wherein the power isolation module further comprises a voltage reduction chip U9, an electrode capacitor C67, a capacitor C68, an electrode capacitor C77, a capacitor C78, a resistor R97 and a light emitting diode D1, wherein:
the Vin end of the voltage-reducing chip U9 is respectively and electrically connected with the Vout + end of the power isolation chip U5, the anode of the electrode capacitor C67 and one end of the capacitor C68, the Vout end of the voltage-reducing chip U9 is respectively and electrically connected with the anode of the electrode capacitor C77, one end of the capacitor C78 and one end of the resistor R97, the Vout end of the voltage-reducing chip U9 is used as the second output of the power isolation module, and the GND end of the voltage-reducing chip U9 is grounded;
the negative electrode of the electrode capacitor C67, the other end of the capacitor C68, the negative electrode of the electrode capacitor C77 and the other end of the capacitor C78 are all grounded;
the other end of the resistor R97 is electrically connected with the anode of the light emitting diode D1, and the cathode of the light emitting diode D1 is grounded.
6. The RS-485 communication activation circuit according to claim 5, wherein the digital isolation module comprises a digital isolation chip U8, a resistor R77, a resistor R76, a resistor R87, a resistor R86, a resistor R66, a resistor R69, a resistor R74, a resistor R78, a capacitor C51, a capacitor C52, a capacitor C54, a capacitor C64, a field effect transistor M3 and a field effect transistor M4, wherein:
the A1 end of the digital isolation chip U8 is electrically connected with the 485TX end of the micro control unit through the resistor R77, the 485TX end of the micro control unit is also electrically connected with one end of a capacitor C51, the 485RX end of the micro control unit is also electrically connected with one end of a capacitor C52, the A2 end of the digital isolation chip U8 is electrically connected with the 485RX end of the micro control unit through the resistor R76, the B1 end of the digital isolation chip U8 is electrically connected with the 485 communication module through the resistor R87, the B2 end of the digital isolation chip U8 is electrically connected with the 485 communication module through the resistor R86, and the VDD1 end and the VDD2 end of the digital isolation chip U8 are connected with a power supply;
one end of the resistor R66 is connected with an SCK clock signal, the other end of the resistor R66 is respectively and electrically connected with one end of the resistor R69 and the gate of the field-effect tube M3, the drain of the field-effect tube M3 is electrically connected with one end of the resistor R74, the other end of the resistor R74 is respectively and electrically connected with one end of the resistor R78 and the gate of the field-effect tube M4, the source of the field-effect tube M4 is respectively and electrically connected with one end of the capacitor C54 and the VDD1 end of the digital isolation chip U8, and the VDD2 end of the digital isolation chip U8 is electrically connected with one end of the capacitor C64;
the other end of the resistor R69, the source of the field effect transistor M3, the other end of the resistor R78, the drain of the field effect transistor M4, the other end of the capacitor C54, the other end of the capacitor C64, the other end of the capacitor C51 and the other end of the capacitor C52 are all grounded.
7. The RS-485 communication activation circuit of claim 6, wherein the second optical coupling module comprises a second optical coupling isolation chip U6, a resistor R70, a resistor R84 and a capacitor C39, wherein:
one end of the resistor R70 is electrically connected with the 485REM end of the micro control unit, and the other end of the resistor R70 is electrically connected with the second input end of the second optical coupling isolation chip U6 and one end of the capacitor C39 respectively;
a second output end of the second optical coupling isolation chip U6 is connected with a power supply, and a second output end of the second optical coupling isolation chip U6 is electrically connected with the 485 communication module and one end of the resistor R84 respectively;
and a second input end of the second optical coupling isolation chip U6, the other end of the capacitor C39 and the other end of the resistor R84 are all grounded.
8. The RS-485 communication activation circuit according to claim 7, wherein the 485 communication module comprises a 485 communication chip U4, a resistor R68, a resistor R93, a resistor R92, an inductor L3, an inductor L2, a capacitor C75, a capacitor C76, an electrode capacitor C69, an electrode capacitor C61, a Zener diode D15 and a Zener diode D14, wherein:
the RO end of the 485 communication chip U4 is electrically connected with the B2 end of the digital isolation chip U8, the DI end of the 485 communication chip U4 is electrically connected with the B1 end of the digital isolation chip U8, the DE end of the 485 communication chip U4 is electrically connected with the second output end of the second optical coupling isolation chip U6 through the resistor R68, the B end of the 485 communication chip U4 is electrically connected with one end of the resistor R93, and the A end of the 485 communication chip U4 is electrically connected with one end of the resistor R92;
the other end of the resistor R93 is electrically connected with one end of an inductor L3, and the other end of the inductor L3 is electrically connected with one end of a capacitor C76, the negative electrode of a voltage stabilizing diode D15 and an external equipment end respectively;
the other end of the resistor R92 is electrically connected with one end of an inductor L2, and the other end of the inductor L2 is electrically connected with one end of a capacitor C75, the negative electrode of a voltage stabilizing diode D14 and an external equipment end respectively;
the other end of the capacitor C76, the anode of the voltage stabilizing diode D15, the other end of the capacitor C75 and the anode of the voltage stabilizing diode D14 are all grounded;
the anode of the voltage-stabilizing diode D15 is also electrically connected with the cathode of the electrode capacitor C69, the anode of the electrode capacitor C69 is electrically connected with the anode of the electrode capacitor C61, and the cathode of the electrode capacitor C61 is connected with an ESD ground wire.
9. The RS-485 communication activation circuit of claim 8, wherein the 485 communication module further comprises a resistor R81, a resistor R80, a capacitor C62 and a capacitor C63, wherein:
the VCC end of 485 communication chip U4 is connected with power, resistance R81's one end, electric capacity C62's one end, electric capacity C63's one end electricity respectively, 485 communication chip U4's GND end and resistance R80's one end are all grounded, resistance R80's the other end and 485 communication chip U4's B termination electricity are connected, R81's the other end and 485 communication chip U4's A termination electricity are connected, electric capacity C62's the other end, electric capacity C63's the other end is all grounded.
10. The RS-485 communication activation circuit according to claim 9, wherein the digital isolation chip U8 uses SI8421AB-D-ISR chip, and the power isolation chip U5 uses B1209S-1WR3 chip.
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| CN202121756876.0U CN215682316U (en) | 2021-07-28 | 2021-07-28 | RS-485 communication activation circuit |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202121756876.0U CN215682316U (en) | 2021-07-28 | 2021-07-28 | RS-485 communication activation circuit |
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