Re: [foxboro] FBM230/Modbus slave too fast problem
- From: "Cleddon" <dmarc-noreply@xxxxxxxxxxxxx> (Redacted sender "cleddon@xxxxxxx" for DMARC)
- To: "foxboro@xxxxxxxxxxxxx" <foxboro@xxxxxxxxxxxxx>
- Date: Thu, 12 Mar 2015 07:55:35 -0400
Since you have a protocol analyzer you can probably use it to drive the slave
and see if the analyzer has any problems with timing. I would also set the
analyzer up as a slave and see where the timing issue starts with the fbm230.
I have done quite a few of these and I have not had a situation where the slave
responded too quickly and especially 2 different devices. As always make sure
you are at the latest rev on the software and don't under estimate the
importance of the cable you are using. An incorrect cable or bad switch setup
can affect the signals to and from the FBM.
Sent from my iPhone
> On Mar 12, 2015, at 6:10 AM, Pablo Lioi <plioi@xxxxxxxxxxx> wrote:
>
> I'm using RTU, but my communication is not a radio link. The FBM230 and the
> slave are inside the same cabinet.
>
>> From: dmarc-noreply@xxxxxxxxxxxxx
>> Subject: Re: [foxboro] FBM230/Modbus slave too fast problem
>> Date: Wed, 11 Mar 2015 15:18:10 -0400
>> To: foxboro@xxxxxxxxxxxxx
>>
>> Are you using Modbus rtu or ASCII? On radio units I have had better luck
>> with Modbus ASCII.
>>
>> Sent from my iPhone
>>
>>> On Mar 11, 2015, at 1:28 PM, Pablo Lioi <plioi@xxxxxxxxxxx> wrote:
>>>
>>> Hi everybody,
>>> I'm sending this again because for some reason carriage returns seem to
>>> have been lost and the post was difficult to read.
>>> In the past I had a serious problem with an FBM230 with Modbus protocol
>>> communicating with a slave using RS-232, in RTU mode.
>>> When the slave response to any query from the master arrived too fast, the
>>> FBM would ignore the response and retry. I finally worked around the
>>> problem delaying the response from the slave a few milliseconds using a
>>> setting (at the slave device) that was meant for radio communication (RTS
>>> to TxD delay).
>>> I am now facing the same problem again, with another slave device. The
>>> problem is that this time I have no way to delay the slave response. I
>>> tried using RTS/CTS handshake on the RS-232 line, but the problem remains.
>>> I know for sure that cable and switch settings at the TA are ok because I'm
>>> looking at the line with a protocol analyser and see correct query and
>>> response messages.I would like to know if somebody else has experienced
>>> this problem too.
>>> Regards
>>> Pablo Lioi
>>> TOTAL AUSTRAL S.A.
>>> Tierra del Fuego - Argentina
>>>
>>>
>>>
>>> _______________________________________________________________________
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>>> Systems (formerly The Foxboro Company). Use the info you obtain here at
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>>
>>
>> _______________________________________________________________________
>> This mailing list is neither sponsored nor endorsed by Invensys Process
>> Systems (formerly The Foxboro Company). Use the info you obtain here at
>> your own risks. Read http://www.thecassandraproject.org/disclaimer.html
>>
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>
>
>
> _______________________________________________________________________
> This mailing list is neither sponsored nor endorsed by Invensys Process
> Systems (formerly The Foxboro Company). Use the info you obtain here at
> your own risks. Read http://www.thecassandraproject.org/disclaimer.html
>
> foxboro mailing list: //www.freelists.org/list/foxboro
> to subscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=join
> to unsubscribe: mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave
>
_______________________________________________________________________
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