MODBUS RTU lag between two redlion g3 graphites

[leblar1]

To make things simple. I am have sometimes severe lag between a G12(slave) and G10(master). When I say severe I mean 1 minute. The G12 is the only slave on that port. I am using Datablocks to in the slave and assigning the tags to the 400001 to 400091 range.

I have set the baud to 38400, 8, 1, even.

This is the master settings are attached.

Thanks for any info.

Andre

 

[jdbrandt]

To make things simple. I am have sometimes severe lag between a G12(slave) and G10(master). When I say severe I mean 1 minute. The G12 is the only slave on that port. I am using Datablocks to in the slave and assigning the tags to the 400001 to 400091 range.

I have set the baud to 38400, 8, 1, even.

This is the master settings are attached.

Thanks for any info.

Andre

Sound extreme.
I would hang a analyser on the data lines, and see what is really going on. I've used 232ANALYSER and Chipkin with good results

Option 1: The transmission is delayed going out.
Option 2: The transmission is going out on time, but the slave is delayed in its response.
Option 3: The transmission is going out, and the response comes in, right away, but the processing of the response takes some time.

You need to figure out which it is.

 

[nwboson]

Have you tried adjusting the Advanced Settings to see if they have any effect: Spanning Reads, Transactional Writes, Favor UI Writes, Comm Delay? I've seen cases where adding a few hundred ms comm delay speeds things up and I'm not smart enough to understand why :-(

Since you are using RS-485, have you experimented with your terminating resistors on each end (add or delete them) to see if that has any effect?

 

[leblar1]

NW,

I'll give that comms delay a shot. I just didn't know where to start. I have been just playing different settings.

 

[Str8jCkt]

Just wondering why you are communicating between the panels over RS-485 and not over ethernet? Is the G12 not hooked up over ethernet?

I have multiple panels linked together using the OPC TCP/IP Master protocol. Set the address of the G12 for your device and select the .cd3 file of the G12 and all its tags become available to the G10 for read or write.

It may reduce the potential for lag.