Internet PLC Forum

General => Technical support => Topic started by: kdebower on March 25, 2013, 10:31:32 AM

Title: Temporarily Suspending Modbus IP
Post by: kdebower on March 25, 2013, 10:31:32 AM

I'm using Mango M2M to communicate with the PLC via Modbus IP.
Sometimes Mango polls the PLC when the PLC's data are not valid, e.g. while reading data from the server, via TLServer.

Is there a way to briefly stop the Modbus during the file reading, for say, a second or so?  Perhaps changing the port number or IP termporarily,  then restoring communications after the data are back in order.

Thanks.

Ken D

Title: Re:Temporarily Suspending Modbus IP
Post by: support on March 29, 2013, 06:58:39 AM

There isn't a documented way to do so. It is probably not a good idea to forcibly shut down an active communication from a master anyway.

One way you can do is to set a flag such as turning on a relay or put a certain value in a DM so that at Mango side it can check for the state of this relay or the value of this DM to tell it whether to accept or discard the data it receives from the PLC during the time when the data is likely to be invalid.