phoenixsmartphonerepair (Customer) asked a question.
Trying to send values to the numeric display to keep track of cycle count.
I am trying to keep track of cycle count for my project on the HMI EA3-S3ML. I am unfamiliar with using holding registers. I tried to write the following.
int cycle_count;
cycle_count = modbusTCPServer.coilWrite(4);
I keep getting an error that the compiler does not understand the code called in this way . Any suggestions
Not sure which Modbus library you're trying to use, but it looks like you're trying to write to a coil and not a holding register.
I am using:
#include <Ethernet.h>
#include <P1AM.h>
#include <ArduinoRS485.h> // ArduinoModbus depends on the ArduinoRS485 library
#include <ArduinoModbus.h>
this is based on the example for the modbus TCP server that is on automationdirect website.
If you have a value stored in "cycle_count" you are trying to display in the HMI at 40005, you could use
modbusTCPServer.holdingRegisterWrite(4,cycle_count);
The function you are calling requires at least two parameters. A modbus address and the value. The optional parameter is unit id that defaults to 0 if one is not provided.
See the modbus library for reference. https://www.arduino.cc/reference/en/libraries/arduinomodbus/
That being said, a coil is used for booleans and such. It's either a 1 or a 0. For integer values you can use a holding register as mentioned before.
Ok but I am not sure how that fixes the communication issue. I am assuming the hmi is not working.
The topic you posted about is for the compile error you had with the code you posted above.
You're communication issue with the HMI is on another topic.
oh my mistake
No problem. Most of the libraries you find for Arduino generally have a reference somewhere on the available functions and how to use them.
Modbus protocol can be a little confusing to understand if you are unfamiliar with it.
Now I am getting a P499:Recv.ErrCode0002 when I select the screens that have numeric displays or numeric entry.
I'm not that familiar with c-more error codes but a look at the manual, seems like the c-more panel is telling there is a modbus illegal address issue.
C-more error codes reference: https://cdn.automationdirect.com/static/manuals/ea3userm/appxa.pdf
P499: C-more reporting a modbus error
0x0002: universal modbus exception error code for 'illegal address'
I would check the tag(s) on the c-more panel are setup correctly that match with what you have setup on the p1am-100.