ION 7650 Modbus Master Coms Failure

[sesa56580_bridg]

For the ION 7650 using the Modbus Master feature is there a reconnect timer when the meter loses coms to a downstream device?

Scenario:

A customer is using an ION 7650 to Modbus Master a generator controller.  When they shut the generator down for maintenance, they completely shut it down - including control power.  In doing this, the ION 7650 loses coms to the generator.  When it comes back online - the meter takes 30 minutes to reconnect.

Is there a setting in the meter that controls this?  Retry timer?

Thanks,

Harvey.

[Yut]

Normally the ION7650 as Modbus Master will keep polling the slaves  every 1 second if the Read Now input of the Modbus Device Importer or Modbus Import module  has no connection. It will poll according the source signal that connected to such as Periodic Timer module the polling interval would be the second setting . If the slave device does not present the polling still continue. Please show more detail how the framework for slave polling was design.

[VictorMarincus]

Hi Harvey,

As Yut mentioned, we need more details about how the framework is programmed in the 7650 / what modules are used and how they are configured.

I would suggest addressing this question to technical support which can perform a deeper analysis of your framework.

Regards,

Victor

[Nabil_Taha]

I'm assuming they are using Modbus TCP to communicate to the generator. We've run into the same issue had to work around it by making a maintenance mode that disables communication when they are doing maintenance on the generator and then reenable after they are completed with maintenance. I have been told that this should be part of a future firmware upgrade.

[sesa56580_bridg]

Thanks Nabil.  Is the firmware upgrade to fix the reconnection issue?  Do you know who I would contact to get more detail on this?

Thanks,

Harvey.

[Nabil_Taha]

Try changing the "Modbus TCP idle timeout" under the Ethernet module to something other than zero and testing that. One of my guys says he tested this and it seemed to work better than the work around we were given.

[sesa56580_bridg]

Thanks.  I will forward the suggestion and see if it resolves anything.

[Anonymous user · Accepted solution]

Yes Harvey there is a timeout on Modbus Master communications.  I believe it tries 3 times at 1 min intervals then enters a 30 mins lockout period.  After 30 mins it will try this process again and if functioning will resume normal operation.  If it fails again it will enter a 30 min timer.

I encourage you to contact technical support with your question as I believe they had derived a custom framework that "might" be able to restore communication earlier than the 30 mins ,however I am not aware if it will work in every case.

Brian

[sesa57310]

As Brian Bikadi mentioned, there is custom framework available to workaround this unfortunate default functionality in the meter.  Please find all the information that you might need about this in the following KB article:

   WORKAROUND AVAILABLE: Modbus Master module on ION7xxx/8xxx devices disables communications for 30 minute periods in response to communications timeouts ( WORKAROUND AVAILABLE: Modbus Master module on ION7xxx/8xxx devices disables communications for 30 mi... )

[sesa56580_bridg]

Thanks Darren!