Probably this is the topic that has already been discussed. I am using Ignition version 7.9.4 to connect to Panasonic FP0H PLCs using Modbus TCP. I am still in the initial stage of device connection. However, the connection status keeps changing from connected to disconnected time to time, and I’m worried if this continues, I might have bad tagging problems. I have searched and tried what other people has mentioned in these forums but they don’t work. I have tried increasing the communication timeout from “2000” up to “30000” but the problem still remains. I also have tried decreasing max holding registers and max input registers to save the scan time but doesn’t work.
I have attached the communication settings for my PLC (hopefully it can be viewed)
I have changed the TCP ULP timeout time to 20*100ms to match my Ignition setting but the problem persists.
Appreciate any help from you guys.
Thanks.
Thank you for your reply.
I also have a problem with subscribing the tags, as I am getting null values all along.
I used holding register 40001-40006 in my PLC, and retrieve the value from Ignition with " [Modbus]HR1 ". Since my stored value in the register is “unsigned integer”, I also tried " [Modbus]HRUS1 " but they both do not work.
I have attached part of my error log since the log file I have is too big to attach.
Hope you could help. Thanks.
You may need to specify a particular unit ID (may be listed as a ‘slave ID’ or something similar in your device configuration). This can be pre-pended to the register path, ie: [Modbus]2.HR1 or similar.
