output module plc circuit Introduction

output module plc power amplifier element driving power plc communication module transistors and DC load, triac drive AC loads, and both can drive an plc programmable intelligent controller load and can drive a small relay DC load. The output current is typically 0.3 ~ 2A, load power provided by the external field.

input module plc choice

input module plc choice
 input module plc choices: 1. Select the power module power module choice is simple, just consider the power supply's rated output current on it. Rated current of the power module must be greater than the total current consumption of the CPU module, I / O modules, and other modules. input module plc select only the modular structure of the PLC, the PLC does Programmable Output Module  not exist for the monolithic power of choice. 2. input module plc programming choice for small control system or PLC system does not require on-line programming, generally used cheap simple programmer. For Chinese and complex systems composed of high-end PLC or need online programming PLC systems can be equipped with powerful, easy programming smart programmer, but a smart programmer expensive. If you have an existing personal computer, you can use the PLC programming software package for programming the function on a personal computer. 3. Writer's choice in order to prevent interference due to plc communication modules  voltage variations and other factors make lithium destruction RAM, users and programs can be selected EPROM writer, through which the user program solidified in EPROM. Now some PLC or EPROM programmer itself has written functions.

How to design output module plc in three-wire constant current source driver circuit

output module plc due to the temperature of the integrated operational amplifier parameters that affect not as a transistor or FET parameters affect significantly the integrated amplifier composed of a constant current plc communication modules  source with the stability better, more constant performance advantages. In particular, the need to ground at the load end of the occasion, received a wide range of applications. Dual op amp constant current source. UA1 amplifier output module plc which constitute adder, 1) load can be grounded; 2) When the op amp is a dual power supply, the output current is bipolar; 3) constant current size adjusted by changing the input reference datum reference resistor Rref0 size to achieve, it is easy to obtain a stable small current calibration and compensation.
Since the resistance of the mismatch, the  plc power supply module voltage across the reference resistor output module plc Rref0 will affect the load end of the driving voltage Vb. The same time as a constant current source, and will definitely change with load changes, which will affect the stability of the constant current source. Obviously, this high-precision constant current source is unacceptable. So R1, R2, R3, R4 selection principle which four resistors is to try a small mismatch, and every size of resistor mismatch direction to be consistent. In practice, a lot of the same batch can be screened precision resistors, where resistance is close to elect four resistors.