I need some help with polling a Modbus TCP device to read some Di's

I have added the Modbus nodes etc as described in the IO manual to the Getting Started project, and mapped the Modbus DiChans to the Dv1-3 in the getting started project.

When I first start the runtime, I see two polls of the Modbus device (which reponds with correct data - no errors)

After this, there are no more modbus query messages created.

Looking the Wireshark to inspect the data on the wire, I see that Proview is constantly establishing a new TCP connection, but closes it before sending the request. This repeats, with no more Modbus query message actually being sent.
The Modbus-slave State becomes \"Disconnected\", but I don't ever see any more Modbus data on the wire.

I have checked the timeout configuration parameter and extended it to be 1000ms, no help. I have also checked the parameter for continuous polling is correctly set.

I have tried polling a read hardware device, and a software Modbus TCP simulator. The results are the same.

I'm using version Proview 4.8 running on Fedora 14.

Any help appreciated.
I can supply more info, Wireshark logs etc. if that helps.

Thanks,
Ben.

Hi,
I don't know what you mean by mapped but you have to create Di objects (not Dv) in the plant hierarchy and connect them to the ChanDi objects by selecting the channel and activate 'Connect channel' in the popup menu for the Di object.

/Claes

Hi,
I have simply extended the getting started project as described in the getting started guide. I have \"connected\" the modbus dichan to di objects. ( I was referring to the di object names in the gsg - \"Dv1 Dv2 Dv3\".)
Ben.

here is a screenshot of the setup...


Basically, I'm just wanting to get some real IO hooked up to this simple project to prove it works before investing to heavily in learning all the details of proview. Looks good (but complex) so far. I just want some real IO going...

thanks for your help.

Ben.

third time lucky?


Post edited by: esixtyone, at: 2010/12/22 03:40