32 Channels 4-20mA MA to 485 AI Current Analog Acquisition Input Module Meter MODBUS RTU

Model: MA420-IN20/32/48/60

This product supports secondary development under PLC, MCGS, Kingview

Instructions on optically isolated 485 communication

In most applications, there is no problem with 485 communication without photoelectric isolation, but in the industrial field, especially in the case of collecting high-precision analog quantities (current, voltage), the interference from the 485 communication line will affect the main board. The working power supply will have a greater impact, which will cause the collected data to jump relatively large. In order to meet the requirements of the industrial field for the stability of the module and the stability of the communication, this module adopts high-speed optocoupler and isolated DCDC regardless of the cost. The power supply module performs photoelectric isolation on the 485 communication line, which completely solves the interference of the 485 communication line on the power supply of the motherboard. The communication interface of some modules on the market is not optically isolated. If the data collected by this product is unstable, Please first consider whether it is because the communication interface is not optically isolated! Simply put: Optoelectronic isolation is better than non-isolation!

Please note before buying: If you want to obtain stable data collection, the 485 communication interface must be photoelectrically isolated. It does not matter whether you buy the products in our store or not, just kindly remind you that this indicator is very important!

Wiring instructions:

24V module working power positive input terminal, DC12V~DC24V

GND Module working power ground

A Isolated 485 signal line A

B Isolated 485 signal line B

VSS isolated 485 signal ground

mAx 0~20mA current source input terminal (relative to GND)

GND 0~20mA current source reference ground wire (common ground with the working power supply of the module)

 Parameter introduction

20/32 road mechanical size: 145*90*40mm (length x width x height)
48/60 road mechanical size: 200*110*60mm (length x width x height)
AD conversion accuracy: 12 bits
Current sampling accuracy: 0.001mA
Current sampling frequency: 5 times/sec
485 interface communication rate: 2400/4800/9600/19200/38400/57600/115200bps adjustable
485 interface communication parity: no parity/odd parity/even parity adjustable
Description of current sampling frequency and communication rate of 485 interface
The current value on the channel read through the 485 interface, the average filtering algorithm is done inside the module, the purpose is to improve the stability of the sampled data, but the side effect of this is to reduce the sampling frequency, so in order to deal with ( The contradiction between the stability of the sampled data and the high-speed acquisition) is to open the parameter of the average number of times used when the module is used for the filtering algorithm to the user. If the user wants the collected data to be more stable, increase this parameter. If high-speed acquisition is to be done, this parameter should be adjusted down; at the same time, the permission to adjust the 485 communication rate and check digit is also opened to users, and the following software is used for configuration, as shown in the following figure: