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Is it possible to use the communication card UniTe/Modbus without using DriveCom and control the drive fully by the Comm.card. VW3-A58303. We want to ...

Goals and Symptoms

Is it possible to use the communication card UniTe/Modbus without using DriveCom and control the drive fully by the Comm.card. VW3-A58303. We want to control the drive via commands on the terminal strip and only READ the status via the comm.card. I tricked it now by using an extra Input with Force Local attached to this input, so my terminal control works and I can still read the status. It seems to me that this should not be neccesary! Is there a more elegant way of doing this? For example write a certain register in the drive so this extra input does not have to be used.

Facts and Changes

ATV38 with VW3-A58303.

Causes and Fixes

For that there is two possibilities:
- Bit 8 =1 and Bit 15 = 1 : Deactivate control
via serial link, in this case you can control the inverter by Li ( terminals ) but send only theses bits to the drive.
- If you don't send the CMD word to the drive and only READ request you can also control the drive by terminals, because in this case, if the inverter never received the CMD word, the control mode is terminals.
These two propositions rae avialble if the master is connected in place of keypad.
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With an option card, by fault the card take the hand on the inverter and it's necessary to disable it, for that bit 3=0 and bit 15=0 of CMD disable Drivecom or bit 15 of CMD force the inverter to a VVD mode ( for industria department ), in this case the Drivecom id disble.

If you don't want send parameter to the inverter, the only solution is Forced local mode.

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