CN205811991U - A kind of D/A transition card of band electrical isolation current/voltage - Google Patents

Abstract

The utility model discloses the D/A transition card of a kind of band electrical isolation current/voltage, it is characterized in that this D/A transition card is by communications transceiver and CPU governor circuit, electrical isolation module, follow driving module and change-over circuit composition, the curtage value that upper-level control system is sent by described communications transceiver accesses CPU governor circuit, the isolation of the treated pulse value input high speed electrical isolation module obtained, filtering and be converted into 0～5V voltage divides two-way to export, one tunnel directly exports after following the driving driving module, another road is accessed change-over circuit after following the driving driving module and is exported with 0～20mA electric current, realize the D/A conversion of band electrical isolation current/voltage.This utility model compared with prior art has short-circuit protection function and a powerful output driving force, circuit logic simple in construction, stable performance, reliable, and capacity of resisting disturbance is strong, and precision is high, maintainable good, low cost, it is simple to enterprise's popularization and application.

Description

A kind of D/A transition card of band electrical isolation current/voltage

Technical field

This utility model relates to controlling number signal transmission technology field, specifically a kind of band in Automated condtrol The D/A transition card of electrical isolation current/voltage.

Background technology

In industrial automatic control, it is frequently necessary to be converted to data volume the analog quantitys such as curtage, to drive as becoming Frequently the industrial motor with analog quantity as input signal such as speed regulator controls device, and existing market has the D/A of polytype and precision Transducer special chip, uses analog form and upper-level control system to carry out electrical isolation, it is difficult to realizing every road driving force can Reach 250mA and short-circuit protection.

The D/A converter of prior art is high with the electrical isolation cost of upper-level control system, and the high frequency of anti-converter Interference, high-power driving ability and short-circuit protection, precision and the linearity are all difficult to meet control requirement.

Utility model content

The purpose of this utility model is a kind of band electrical isolation current/voltage designed for the deficiencies in the prior art D/A transition card, uses the pulsewidth modulation of fixed cycle variable duty ratio, it is achieved electric current and the voltage of band electrical isolation are same in high precision Time output, make the electric current of output and voltage completely isolated with upper-level control system, short-circuit protection, precision and the linearity can be met Controlling requirement, output driving force is strong, not only simple in construction, good in anti-interference performance, stable performance, reliable, and maintainable Good, production cost is low.

The purpose of this utility model is achieved in that the D/A transition card of a kind of band electrical isolation current/voltage, its feature It is this D/A transition card by band electrical isolation RS485 communications transceiver and CPU governor circuit, high speed electrical isolation module, follows and drive Galvanic electricity die block and voltage/current conversion circuit are sequentially connected in series composition, and described band electrical isolation RS485 communications transceiver is by upper The curtage controlling value that the communication of control system MODBUS sends accesses CPU governor circuit；Described CPU governor circuit is by electric current Or the width-modulation pulse value input high speed electrical isolation module that voltage controling value obtains through calculation process；Described High-speed Electric air bound From module, variable impulse width is modulated pulse value and carry out Isolation, and be converted into point two-way output after 0～5V voltage, a road warp Accessing voltage/current conversion circuit after following the driving of driving voltage module, another road is through following the driving of driving voltage module Rear directly output；0～5V voltage is converted to 0～20mA electric current output by described voltage/current conversion circuit, it is achieved charged air bound Change from the D/A of current/voltage.

This utility model compared with prior art has short-circuit protection function and powerful output driving force, circuit logic Simple in construction, stable performance, reliable, capacity of resisting disturbance is strong, and precision is high, maintainable good, low cost, it is simple to enterprise promotes should With.

Accompanying drawing explanation

Fig. 1 is this utility model structural representation；

Fig. 2 is that this utility model specifically uses schematic diagram.

Detailed description of the invention

Refering to accompanying drawing 1, this utility model is by band electrical isolation RS485 communications transceiver 1 and CPU governor circuit 2, High-speed Electric Gas isolation module 3, follow driving voltage module 4 and voltage/current conversion circuit 5 is sequentially connected in series composition, described band electrical isolation The communication of upper-level control system MODBUS is sent the curtage controlling value come and delivers to CPU master control electricity by RS485 communications transceiver 1 Road 2；Described CPU governor circuit 2 in making full use of selected CPU five PCA modules of peculiar hardware resource wherein four modules and Powerful assemble software function, sends, according to the communication of upper-level control system MODBUS, the curtage controlling value of coming, through computing Process obtains M₃、M₂、M₁And M₀The width-modulation pulse value input high speed electrical isolation module of four fixed cycle variable duty ratios 3；Described high speed electrical isolation module 3 is by M₃、M₂、M₁And M₀Variable impulse width modulation pulse value carries out Isolation, and is converted into 0 ～driving voltage module 4 is followed in input after 5V voltage；Described follow driving voltage module 4 will drive after high-power 0～5V electricity While pressure directly output, and it is inputted voltage/current conversion circuit 5；Described voltage/current conversion circuit 5 is by 0～5V Voltage is converted to 0～20mA electric current and sends, and ultimately forms completely self-contained four tunnel 0～20mA electric currents and four tunnel 0～5V voltages are defeated Go out, to adapt to the input control signal requirement of industry spot difference motor speed regulation equipment.

The specific embodiment controlled with four motor variable-frequency speed-regulatings of industry spot below, makees further this utility model Describe in detail.

Embodiment 1

Refering to accompanying drawing 2, this utility model accesses four frequency change speed regulator for motors 6 being connected with on-the-spot motor 7, four motors The communication of upper-level control system MODBUS is sent the different electricity come by variable-frequency governor 6 by band electrical isolation RS485 communications transceiver 1 Motor speed controlling value delivers to CPU governor circuit 2, obtains the pulsewidth modulation arteries and veins of four fixed cycle variable duty ratios through calculation process Punching value, this pulse is delivered to follow by being converted into the magnitude of voltage of 0～5V after the Isolation of high speed electrical isolation module 3 Driving voltage module 4, produces one high-power 0～the output of 5V voltage, simultaneously by 0 after following the driving of driving voltage module 4 ～5V delivers to voltage/current conversion circuit 5, it is defeated that 0～5V voltage is converted to 0～20mA electric current by voltage/current conversion circuit 5 Go out, according to different requirement of converter, 0～20mA electric current output or the output of 0-5V voltage can be received four variable-frequency governors 6, 0～20mA electric current or 0～5V voltage are converted to 0～50Hz frequency and access on-the-spot motor 7, every change by four variable-frequency governors 6 Frequently one alternating current generator of governor control, analog DC voltage 0V for shutting down, analog DC voltage be 5V motor speed the fastest or Analog DC 0mA is for shutting down, and analog DC is that 20mA motor speed is the fastest, thus reaches on-the-spot motor 7 frequency conversion The purpose of speed regulating control operating.

This utility model applies peculiar hardware five PCA modules wherein four module hardwares in making full use of selected CPU Resource and powerful assemble software function, make circuit logic structure very simple, and hardware cost is low, controls speed fast, and precision is high, Cost performance is good, reliable and stable, and capacity of resisting disturbance is strong, maintainable good, makes the performance of enterprises and social benefit reach optimal.Above only That this utility model is described further, and be not used to limit this patent, all for this utility model equivalence implement, all should comprise Within the right of this patent.

Claims (1)

1. the D/A transition card of a band electrical isolation current/voltage, it is characterised in that this D/A transition card is by band electrical isolation RS485 communications transceiver (1) and CPU governor circuit (2), high speed electrical isolation module (3), follow driving voltage module (4) and Voltage/current conversion circuit (5) is sequentially connected in series composition, and described band electrical isolation RS485 communications transceiver (1) is by upper control system The curtage controlling value that system MODBUS communication sends accesses CPU governor circuit (2)；Described CPU governor circuit (2) is by electric current Or width-modulation pulse value input high speed electrical isolation module (3) that voltage controling value obtains through calculation process；Described High-speed Electric Variable impulse width is modulated pulse value and is carried out Isolation by gas isolation module (3), and is converted into point two-way output after 0～5V voltage, Voltage/current conversion circuit (5) is accessed after following driving voltage module (4) and driving in one tunnel, and another road is through following driving voltage Module (4) directly exports after driving；It is defeated that 0～5V voltage is converted to 0～20mA electric current by described voltage/current conversion circuit (5) Go out, it is achieved the D/A conversion of band electrical isolation current/voltage.