Welcome Guest ( Login | Register )



All times are UTC - 7 hours [ DST ]



Post new topic Reply to topic  [ 1 post ] 
Author Message
 Post subject: iX and Modbus slave
PostPosted: Fri May 22, 2015 9:36 am 

Joined: Mon Aug 19, 2013 1:32 pm
Posts: 14

Offline
QTerm-A12 with the latest iX.

The A12 connects to an embedded controller with Modbus serial to exchange data. The A12 is the slave; the iX Modbus driver is Modbus Slave 4.16.02. The embedded controller is the master. A holding register is incremented at fixed rate by the master. The A12 checks this heartbeat tag every second, if the heartbeat did not change after 5 consecutive checks, the datalink alarm is triggered and displayed on the Alarm Viewer.

If the system is run long enough, say overnight, we would see the datalink alarm. Log records from the embedded controller indicates the A12 failed to reply. The SystemTagCPULoad is typical at 20-35%. We added a few CPU load counter tags; the 95% tag recorded a count of 3-4 overnight.

We assigned tags to all 5 pollgroups with 500, 750, 1000, 1500, 2000ms to reduce the update rate. We implemented hints in "optimizing iX application.pdf"

What causes the A12 to spike beyond 95% CPU load at idle?

We are not sure if the CPU load spike caused the Modbus comm error since it doesn't happen often. There are 713 tags mapped to the ModBus registers. Is this within the A12's capacity?

What do the Timeout and Retries settings in the Modbus Slave Setting dialog do for the slave? The A12 is the Slave, it only replies.

What else to try?


 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 1 post ] 

All times are UTC - 7 hours [ DST ]


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to: