Modbus TCP Connection Down -7001
We have one CI867 unit used with AC800M Controller PM856. We noticed that the TCP connection is up and down (Icon turning yellow and red alternately at hardware tree).
So when we disable the MBTCP Read block in application, and only enable MBTCP Connect Block, the status is showing 1 and -7001 alternately.
Anyone face the same issue before and can share how you solve this matter?
Voted best answer
The status -7001 for MBTCP Connect block means Third party communication connection down.
1. It may be not pinging continuously. Check the modbus network. Ping the slave TCP device and confirm if it is pinging continuously for a while without timedout error msg.
"Ping xxx.xxx.xxx.xxx -t"
2. If pinging succeeded, the slave TCP device may often open and close its TCP ports. Hence check the slave device configuration like allowed master IP settings etc,. I recommend to connect and check Modscan Modbus Master simulator with slave device to confirm the communication, before bring to our CI867 modbus network.
For AC500 slaves you should use Modbus TCP IP Server (= slave for Modbus TCP/IP) and I can recommend fixed cycle time for your tasks !
I faced such a communication problem, when using of freewheeling tasks.
Try with pool time = 0 for CI867
Also for slave address use 2, 3 and up (not recommended 1)