Random Hardware Watchdog

[jcb]

We have a system we retrofitted from directlogic to BRX. It relies heavily on DLRX and DLWX comms to the older systems and I feel like this might play a part in the issue but am not sure.

There are VFD's close by in the cabinet although they are separated with a Barrier and everything is grounded and shielded properly. The old PLC never had issues with them. This PLC is the controller for them and some closed loop hydraulic pumps used in a planer system. Everything works fine when it is running but on occasion will reboot or drop to program mode.

I recently loaded the newest firmware and slowed down the COMMS to 250ms from 50ms to see if it would help but it dropped out again after that.

Here is the System Logs and Watchdog information.

Thanks
John.

[Greg]

We have a system we retrofitted from directlogic to BRX. It relies heavily on DLRX and DLWX comms to the older systems and I feel like this might play a part in the issue but am not sure.

There are VFD's close by in the cabinet although they are separated with a Barrier and everything is grounded and shielded properly. The old PLC never had issues with them. This PLC is the controller for them and some closed loop hydraulic pumps used in a planer system. Everything works fine when it is running but on occasion will reboot or drop to program mode.

I recently loaded the newest firmware and slowed down the COMMS to 250ms from 50ms to see if it would help but it dropped out again after that.

Here is the System Logs and Watchdog information.

Thanks
John.

John, it doesn't look like there's been a response to this. Did you chat with anyone else via email?

Anyways, the codes in the pic do not look abnormal. They're regular codes seen on a normal power up.

Regarding DST411 ($DebugTrapAddr), note its value (store it off somewhere if you want) after a reboot (or just look at it in Data View), then clear it to zero in preparation for the next possible reboot.

• If it is the same value after a reboot, it could be a bug in our firmware.
• If it is never set to a value (i.e. it remains zero after every reboot), or it has random values in it, then it could be a communication issue or noise.

[jcb]

No I hadn't heard anything so just figured i would keep moving forward with the BRX upgrades.

We are upgrading one of the other PLC's that this one communicates with to BRX and are going to switch over tomorrow. I figured I would see if the problems went away after that.

I have had 3 more watchdogs since my last posting but we have been doing a lot more communication with the old DirectLogic PLC to the new BRX we are installing in it's place so that might point to it be a communication issue.

If it doesn't get better after that I'll keep trying to figure out how to duplicate it or see if i can isolate the issue to a specific section of code.

The DST411 ($DebugTrapAddr) is still 0 so probably something in the cabinet or bad Ethernet comms.


Thanks,
John.

[Greg]

No I hadn't heard anything so just figured i would keep moving forward with the BRX upgrades.

We are upgrading one of the other PLC's that this one communicates with to BRX and are going to switch over tomorrow. I figured I would see if the problems went away after that.

I have had 3 more watchdogs since my last posting but we have been doing a lot more communication with the old DirectLogic PLC to the new BRX we are installing in it's place so that might point to it be a communication issue.

If it doesn't get better after that I'll keep trying to figure out how to duplicate it or see if i can isolate the issue to a specific section of code.

The DST411 ($DebugTrapAddr) is still 0 so probably something in the cabinet or bad Ethernet comms.


Thanks,
John.

One of the things we added is more debug information for troubleshooting a reboot caused by comms.

So, with what other things is it talking?

In Data View you can check out DST72 ($FreePackets). Its value should hover around 375. If it starts trending downward, turn ON ST300. This causes memory to fill with connection data (DST98-399 will now contain data of what is using sessions).

Also, if you turn ON ST301, then it will put data into DST200-205. These values can be helpful to us as well.

[jcb]

It is using DLRX and DLWX to Exchange V DATA with 3 other Directsoft PLC's. It's not a whole lot of comms but there is a lot of Communication on that Network Segment as there are 5 DirectLogic DL06's PLC's acting as Slaves talking to a DirectSoft DL-06 Master. This is the system we are going to be converting to BRX and Remote IO.

Most Days there are warning messages about failed Comms that we can't really pin down. We are also going to be replacing the network switches and attempting to isolate that subnet from the rest of the plant. This is why i wasn't to worried about it. Eventually we will have the whole thing upgraded to BRX and Gigabit ethernet switches and no broadcast traffic.

As far as this PLC.. It is hovering around 375.

I added a few rungs to out ST300 and 301 if the Free Packets Drops under 300 and increment a counter.

I will let you know what i find.

Thanks Again.
John.