Curious MODBUS TCP polling fault

[dan]

Hey Guys, having a really strange problem with our MODBUS TCP data source.
We have a bunch of solar regulators and a bunch of genset controllers (via Moxa MB3180 converters). Both talk MODBUS / TCP and have all been working up until recently where all the genset controllers (4 in this network) stopped responding.
The solar regulators are however still working fine.
All data points in the genset controllers are coming up as unreliable, and are not reporting at all.
Here is the error I get when trying to interrogate a data point directly...

I've never seen that error before, I tried a quick google and it's pointing towards misconfiguration or overloading of a datapoint, this doesn't seem right as nothing's changed apart from a new instance of Mango on that site.
The solar regulators using the same type of MODBUS TCP client are still working, just the gensets aren't responding.

I turned on specific data logging on that data source and got the following, I see I'm getting some kind of response judging by the I and O?

2018/05/01-13:26:20,240 O 001c00000006010475320019
2018/05/01-13:26:20,261 I 001c0000000301840a
2018/05/01-13:27:20,241 O 001d00000006010475320019
2018/05/01-13:27:20,261 I 001d0000000301840a
2018/05/01-13:28:20,241 O 001e00000006010475320019
2018/05/01-13:28:20,261 I 001e0000000301840a
2018/05/01-13:29:20,241 O 001f00000006010475320019
2018/05/01-13:29:20,261 I 001f0000000301840a

Any ideas would be much appreciated.

Cheers
Dan

[phildunlap]

Hi Dan,

"Gateway path unavailable" is a specific Modbus exception code (Exception code 10, or 0x0a) for devices acting as gateways (I assume either IP or serial). It means the device acting as the gateway doesn't believe the request will get through, I'd say. I did a little googling and people seemed to say the gateway device is either misconfigured, overwhelmed, or just faulting. I would wonder why it decided slave 1 was unavailable.

[dan]

Hey Phillip, thanks for that. For the gensets, we're running Moxa MB3180 RS485 - Ethernet MODBUS gateways, they have worked until we put a new instance of Mango in. They also work fine on all of our other sites.
I will see if I can get some more debugging out of the gateways.

Cheers
Dan

[phildunlap]

they have worked until we put a new instance of Mango in

I'm not aware of any changes in the Modbus4J code in quite some time. Certainly none at the protocol level.