MVI56-MCM
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frosty
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Monday 09 August 2004 7:46:22 pm |
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MVI56-MCM
We have found that the Modbus Database held by the MVI56 - MCM is presistent. That is the data remains at its last values even if communications to the remote device are lost. Does anyone know how to change this behaviour to cause the database to be set to default values or zeros if communications are lost after the retry period.
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mtracy
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Tuesday 10 August 2004 8:40:46 am |
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RE:MVI56-MCM
The database within the MVI56-MCM is retentive for safety reasons. The MCM module will not generate any data, including 0s, without input from the Modbus network.
There is no way to 0 the register space without power cycling the module.
If you are using the MCM as a Modbus master, then you can use the Master Command Error table to determine if the data withing the register space is valid or not.
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Esander
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Monday 27 June 2005 6:11:54 pm |
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RE:MVI56-MCM
I'm also using the MVI56-MCM and ran into the problem of kept information after Communication lost. I saw the answer of MTracy but can't find the Master Command Error table in de demo Ladder. Can someone pleae help me with reading the Master Command Error table.
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jsanders
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Tuesday 28 June 2005 3:33:56 am |
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RE:MVI56-MCM
You use the tag, MCM.PortX.CmdErrPtr (where X is the Master Port), to point the Command Error Table into an unused area of your ReadData array so you can see the status of each command. For instance, in your application, if MCM.ModDef.ReadStartReg=600 and you are not already using MCM.ReadData[500] through [599] for data, you could get the Command Error Table to appear in those addresses by setting the MCM.PortX.CmdErrPtr=1100 (ReadData[0]=MCM.ModDef.ReadStartReg=module address 600; so ReadData[500]=module address 1100.)
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