CN201716293U

CN201716293U - Combustible gas concentration acquisition module

Info

Publication number: CN201716293U
Application number: CN2010202571372U
Authority: CN
Inventors: 秦旭昌; 邵开春; 潘广斌
Original assignee: JINAN CHANGQING COMPUTER APPLICATION CO Ltd
Current assignee: JINAN CHANGQING COMPUTER APPLICATION CO Ltd
Priority date: 2010-07-13
Filing date: 2010-07-13
Publication date: 2011-01-19
Anticipated expiration: 2020-07-13

Abstract

The utility model discloses a combustible gas concentration acquisition module and belongs to a detecting instrument, particularly an instrument component for carrying out data acquisition on combustible gas concentration. The acquisition module mainly comprises a switching power supply circuit, current acquisition circuits, a main control circuit which uses a PIC16F690 singlechip and a 485 communication circuit. The main control circuit which uses the PIC16F690 singlechip adopts the following structure that input pins 7, 8, 9, 13, 14, 15, 16, 17 of an internal A/D conversion circuit of the PIC16F690 singlechip IC2 are respectively connected with 8 paths of current acquisition circuits; tenth and twelfth pins of the IC2 used as USART are connected with the 485 communication circuit; second and third pins of the IC2 are connected with an external crystal oscillator; and a fifth pin of the IC2 is connected with a working state indicating circuit. The utility model realizes simultaneous acquisition of 8 paths of current signals by sufficiently utilizing the function of the internal A/D conversion circuit of the singlechip. The 485 communication circuit can send and remotely transmit the information to monitoring and control equipment at any time. The combustible gas concentration acquisition module is also provided with the design of preventing reverse connection of a power supply and protecting overvoltage and overcurrent and improves reliability of the equipment.

Description

The combustable gas concentration acquisition module

Technical field

The utility model belongs to a kind of detecting instrument, especially for the instrument component that combustable gas concentration is carried out data acquisition.

Background technology

Place using inflammable gas usually needs to be provided with a large amount of combustable gas concentration checkout equipments in order to ensure safety, and existing combustable gas concentration acquisition system is that single channel detects mostly, and the number of devices that needs is many, and complex management is unfavorable for centralized control.

The utility model content

Detect in order to overcome existing combustible gas collecting device single channel, be unfavorable for central controlled deficiency, the purpose of this utility model provides a kind of combustable gas concentration acquisition module, and this combustable gas concentration acquisition module can be gathered multichannel combustible gas concentration information simultaneously.

The technical scheme that its technical matters that solves the utility model adopts is: a kind of combustable gas concentration acquisition module, it is characterized in that: mainly comprise switching power circuit, the current acquisition circuit, use the governor circuit of PIC16F690 single-chip microcomputer, 485 communicating circuits, the governor circuit structure of described use PIC16F690 single-chip microcomputer is: the input pin 7 of the built-in A/D change-over circuit of PIC16F690 single-chip microcomputer IC2,8,9,13,14,15,16,17 are connected with 8 road current acquisition circuit respectively, the 10th of IC2 is connected with 485 communicating circuits as USART with the 12nd pin, 2 pin of IC2 are being connected external crystal oscillator with 3 pin, and 5 pin of IC2 connect the duty indicating circuit.

The chip IC 1 of described switching power circuit adopts the LM2575-5 chip, convert 24V to 5V, its circuit connecting mode is 3 pin and the 5 pin ground connection of IC1, between 1 pin of IC1 and the ground electrolytic capacitor filter E1 is housed, 2 pin of IC1 connect the negative electrode of D2 and form the PWM oscillating circuit, 4 pin of IC1 are the feedback pin, and L3 and E2 form output filter circuit.

Also be provided with on the described switching power circuit and anti-connect anti-and its structure of current foldback circuit is: the anode of diode D1 connects the 24V connection terminal, the negative electrode connection PTC1 of D1, and the PTC1 other end is through discharge tube ground connection.

The structure of described current acquisition circuit is: enter R11 after the holding circuit that current signal is formed through PTC4 and BS4 and change to such an extent that voltage signal enters the 7 pin LM385 mu balanced circuit WY2 that enter IC2 after the filtering circuit filtering interfering that R12 and C8 form and is connected in parallel on the C8 two ends.

Described 485 communicating circuit structures are: the 10th pin of IC2 is that the serial ports of PIC16F690 single-chip microcomputer sends pin, be responsible for outwards sending data, 4 pin that connect IC3,12 pin of IC2 are that the serial ports of PIC16F690 single-chip microcomputer sends pin, 1 pin that connects IC3, after 4 pin of IC3 receive information, IC3 becomes the RS485 differential signal to send on the RS485 bus information translation, IC3 receives the information from the RS485 network simultaneously, convert the TTL signal to and pass to 12 pin of IC2 by 1 pin of IC3,2 pin of IC3 and 3 pin are connected in parallel and are connected to 11 pin of IC2, as RS485 bus transmitting-receiving control signal, when 11 pin of IC2 are exported high level, IC3 sends data to the RS485 bus, when the 11 pin output low levels of IC2, IC3 receives data from the RS485 bus, and 5 pin of IC3 are power supply ground connection GND, 8 pin of IC3 be power supply just, link 5V by L6,6 pin of C3 and 7 pin are respectively the A+ and the B-signal of RS485 bus, and described RS485 bus transceiving chip is sn65hvd3082.

Described external crystal oscillator structure is: 2 pin of IC2 are connected the two ends of JZ (frequency is the accurate crystal oscillator of 11.0592MHz) with 3 pin, be connected to GND by capacitor C 5 and C6 by 22pF.

Described duty indicating circuit structure is: 5 pin of IC2 connect R5 one end, the flicker of control LD1, and glimmer once p.s., and the R5 other end connects the anode of LD1, and the negative electrode of LD1 connects GND.

The utility model makes full use of function that the PIC16F690 single-chip microcomputer possesses built-in A/D change-over circuit and makes this module realize gathering simultaneously 8 road current signals such as input end the combustable gas concentration sensor is installed just can be gathered the combustible gas concentration information of 8 variant positions simultaneously; 485 communicating circuits can send these information at any time and monitoring and opertaing device are arrived in teletransmission owing to be provided with; the utility model also is provided with anti-power supply reversal connection and over-voltage over-current protection can be avoided misoperation or other damage equipment, has improved the reliability of equipment.

Description of drawings

Fig. 1 is a circuit structure block scheme of the present utility model,

Fig. 2 is a power circuit synoptic diagram among Fig. 1,

Fig. 3 is a governor circuit synoptic diagram among Fig. 1,

Fig. 4 is a communicating circuit synoptic diagram among Fig. 1,

Fig. 5 is an Acquisition Circuit synoptic diagram among Fig. 1.

Among the figure, 1. communication signal output port, 2.485 communicating circuits, 3. crystal-oscillator circuit, 4. governor circuit, 5. switching power circuit, 6. duty indicating circuit, 7. current acquisition circuit, 8. current signal input port.

Embodiment

Embodiment of the present utility model is, as shown in the figure:

Embodiment 1, a kind of combustable gas concentration acquisition module, its structure is: mainly comprise switching power circuit 5, current acquisition circuit 7, use the governor circuit 4 of PIC16F690 single-chip microcomputer, 485 communicating circuits 2, the governor circuit structure of described use PIC16F690 single-chip microcomputer is: the input pin 7 of the built-in A/D change-over circuit of PIC16F690 single-chip microcomputer IC2,8,9,13,14,15,16,17 are connected with 8 road current acquisition circuit respectively, the 10th of IC2 is connected with 485 communicating circuits as USART with the 12nd pin, 2 pin of IC2 are being connected external crystal oscillator with 3 pin, and 5 pin of IC2 connect duty indicating circuit 6.The current acquisition circuit connects the current input terminal mouth, and 485 communicating circuits connect the communication signal output port.

Also be provided with on the described switching power circuit and anti-connect anti-and its structure of current foldback circuit is: the anode of diode D1 connects the 24V connection terminal, the negative electrode connection PTC1 of D1, and the PTC1 other end is through discharge tube ground connection.When power supply wiring just often; D1 is equivalent to lead; the PN junction pressure drop of 0.7V is only arranged self; when 24V connects inverse time, the GND-BUS mistake be connected to 24V, if there is not the protection of D1 will burn out IC1; because the existence of D1; its PN junction oppositely by, whole loop is cut off, protected internal circuit effectively.

The structure of described current acquisition circuit is: enter R11 after the holding circuit that current signal is formed through PTC4 and BS4 and change to such an extent that voltage signal enters the 7 pin LM385 mu balanced circuit WY2 that enter IC2 after the filtering circuit filtering interfering that R12 and C8 form and is connected in parallel on the C8 two ends, the connection terminal of the end link block of PTC4, the other end connects BS4 and forms overcurrent and overvoltage crowbar, PTC4 is a resettable fuse, BS4 is a discharge tube, when voltage during greater than 6V, BS4 is to the GND conducting, electric current moment infinity, the PTC4 size fusible circuit, breaker, thereby protection Acquisition Circuit, after threatening (be higher than the voltage of 6V or be higher than the electric current of 100mA) not exist, PTC4 recovers conducting, do not influence the module operate as normal, enter R11 after the holding circuit of 4-20mA signal through PTC4 and BS4 composition, the resistance value of R11 is 100 ohm, according to U=IR formula: Umin=0.004 * 100=0.4V; Umin=0.02 * 100=2V.Therefore voltage signal after the conversion has the electromagnetic interference (EMI) that amplitude is 100mV, changes to such an extent that voltage signal enters 7 pin of the laggard IC2 of filtering circuit filtering interfering of R12 (10K resistance) and C8 (0.1uF electric capacity) composition through R11.7 pin of IC2 are the built-in AD converter of PIC16F690 single-chip microcomputer, and filtered voltage signal is converted to the digital signal of 0-100%LEL by AD converter.WY2 (LM385 mu balanced circuit, loop voltage are forced to be stabilized in 2.5V when surpassing 2.5V)

Described 485 communicating circuit structures are: the 10th pin of IC2 is that the serial ports of PIC16F690 single-chip microcomputer sends pin, be responsible for outwards sending data, 4 pin that connect IC3,12 pin of IC2 are that the serial ports of PIC16F690 single-chip microcomputer sends pin, connect 1 pin of IC3, after 4 pin of IC3 received information, IC3 became the RS485 differential signal to send on the RS485 bus information translation, IC3 receives the information from the RS485 network simultaneously, converts the TTL signal is passed to IC2 by 1 pin of IC3 12 pin to.2 pin of IC3 and 3 pin are connected in parallel and are connected to 11 pin of IC2, as RS485 bus transmitting-receiving control signal, when 11 pin of IC2 output high level, IC3 sends data to the RS485 bus, when the 11 pin output low levels of IC2, IC3 receives data from the RS485 bus, 5 pin of IC3 are that power supply ground connects GND, 8 pin of IC3 be power supply just, link 5V by L6,6 pin of C3 and 7 pin are respectively the A+ and the B-signal of RS485 bus, and described RS485 bus transceiving chip is sn65hvd3082.

Claims

1. combustable gas concentration acquisition module, it is characterized in that: mainly comprise switching power circuit, the current acquisition circuit, use the governor circuit of PIC16F690 single-chip microcomputer, 485 communicating circuits, the governor circuit structure of described use PIC16F690 single-chip microcomputer is: the input pin 7 of the built-in A/D change-over circuit of PIC16F690 single-chip microcomputer IC2,8,9,13,14,15,16,17 are connected with 8 road current acquisition circuit respectively, the 10th of IC2 is connected with 485 communicating circuits as USART with the 12nd pin, 2 pin of IC2 are being connected external crystal oscillator with 3 pin, and 5 pin of IC2 connect the duty indicating circuit.

2. according to the described combustable gas concentration acquisition module of claim 1, it is characterized in that: the chip IC 1 of described switching power circuit adopts the LM2575-5 chip, convert 24V to 5V, its circuit connecting mode is 3 pin and the 5 pin ground connection of IC1, between 1 pin of IC1 and the ground electrolytic capacitor filter E1 is housed, 2 pin of IC1 connect the negative electrode of D2 and form the PWM oscillating circuit, and 4 pin of IC1 are the feedback pin, and L3 and E2 form output filter circuit.

3. according to claim 1 or 2 described combustable gas concentration acquisition modules; it is characterized in that: also be provided with on the described switching power circuit and anti-connect anti-and its structure of current foldback circuit is: the anode of diode D1 connects the 24V connection terminal; the negative electrode of D1 connects PTC1, and the PTC1 other end is through discharge tube ground connection.

4. determine the combustable gas concentration acquisition module according to claim 1, it is characterized in that: the structure of described current acquisition circuit is: enter R11 after the holding circuit that current signal is formed through PTC4 and BS4 and change to such an extent that voltage signal enters the 7 pin LM385 mu balanced circuit WY2 that enter IC2 after the filtering circuit filtering interfering that R12 and C8 form and is connected in parallel on the C8 two ends.

5. determine the combustable gas concentration acquisition module according to claim 1, it is characterized in that: described 485 communicating circuit structures are: the 10th pin of IC2 is that the serial ports of PIC16F690 single-chip microcomputer sends pin, be responsible for outwards sending data, 4 pin that connect IC3,12 pin of IC2 are that the serial ports of PIC16F690 single-chip microcomputer sends pin, 1 pin that connects IC3, after 4 pin of IC3 receive information, IC3 becomes the RS485 differential signal to send on the RS485 bus information translation, IC3 receives the information from the RS485 network simultaneously, converts the TTL signal is passed to IC2 by 1 pin of IC3 12 pin to.2 pin of IC3 and 3 pin are connected in parallel and are connected to 11 pin of IC2, as RS485 bus transmitting-receiving control signal, when 11 pin of IC2 output high level, IC3 sends data to the RS485 bus, when the 11 pin output low levels of IC2, IC3 receives data from the RS485 bus, 5 pin of IC3 are that power supply ground connects GND, 8 pin of IC3 be power supply just, link 5V by L6,6 pin of C3 and 7 pin are respectively the A+ and the B-signal of RS485 bus, and described RS485 bus transceiving chip is sn65hvd3082.

6. determine the combustable gas concentration acquisition module according to claim 1, it is characterized in that: described external crystal oscillator structure is: 2 pin of IC2 are connected the two ends of accurate crystal oscillator JZ with 3 pin, by being connected to GND by capacitor C 5 and C6.

7. determine the combustable gas concentration acquisition module according to claim 1, it is characterized in that: described duty indicating circuit structure is: 5 pin of IC2 connect R5 one end, the flicker of control LD1, and glimmer once p.s., the R5 other end connects the anode of LD1, and the negative electrode of LD1 connects GND.