SIEMENS_ S7-200 collects 64 analog channels

Industrial sites often encounter the need to use PLC to collect multiple analog quantities, especially thermocouple and thermal resistance signals. The following provides a Siemens S7-200 with four S1116 (Beijing Simhong product) front-end modules to collect 64 analog quantities, which will be shared with colleagues in the industrial control field.
S1116 is an analog input front-end for 16 channel input. After software setting, it can directly input various signals of standard voltage, current, thermal resistance and thermocouple, including 0~5V, 0~10V, 0~50mV, 0~10mA, 4~20mA, Pt100, Cu50, K graduation, S graduation, etc., which can be freely mixed input. Channels are isolated with precision of 0.2 and RS485 communication interface.
The steps for Siemens S7-200 to connect four S1116 to collect 64 analog quantities are as follows:
（1） The user uses the S-Series and S3000 Series Setting Test Software to set the channel parameters and verify the accuracy on the computer according to the site requirements. The communication station addresses of 4 S1116 are respectively set as 1, 2, 3 and 4, the communication rate is set as 38400bps, and the communication protocol is S_ PLC。
（2） Connect the RS485 communication interface of S7-200 (take 226 as an example) and the RS485 communication interface of four S1116 in series with twisted pair, and connect the three pins of S7-200 communication interface (nine core) to the 37 terminals (485+) of four S1116; The 8-pin of S7-200 communication port (9-core) is connected to 4 36 terminals (485 -) of S1116; Five pins of S7-200 communication port (nine core) are connected to four 35 terminals (485 ground) of S1116.
（3） Fill the connection program (program sequence name is S_PLC) between the S series I/O front end and S7-200 provided by Beijing Simhong on the S7-200, and modify the number definition unit (VB3900) and the model definition unit (VB3902, VB3903, VB3904, VB3905) of the corresponding hooking front end according to the program instructions.
（4） Running this program, you can immediately see the engineering quantity value of 64 analog quantities to be collected (temperature is what degree, pressure is what MPa, integer number) in the corresponding data mapping area (128 bytes in total from VB4000 to VB4128).
It's that simple. This method can collect 512 analog quantities or 1024 switching quantities (32 station hours), and can also be used to control the output of multiple analog quantities or switching quantities