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There is an application with Altivar 38 with pump switching card where the auxiliary pump is driven by an Altistart 48.There is also Modbus connection...

Goals and Symptoms

There is an application with Altivar 38 with pump switching card where the auxiliary pump is driven by an Altistart 48.There is also Modbus connection where the master is a Twido PLC and the slaves are the ATV38 and the ATS 48. The problem is that en error ERR 7 (erreur LS) is appeared at the ATV38 display.What kind of error is that and what can we do about it?

Facts and Changes

ATV38 with Modbus connection

Causes and Fixes

Product trips transiently to "Err3" or "Err7" fault. Both faults type are generated by the display module.
This one communicates with the microprocessor of control card .
When incorrect messages occur during the communication and after some repetition of exchanges , the display module shows to "ErrX".
This is a very difficult fault to reproduce because depending of environment ( lenght of wire between display module and control board , motor running, disrupted site ) and the combination between display module and control board.

Origin of problem :

Insufficient immunity of communication facing the various disturbances.
The communication frames managing is made by integrated components called "drivers". One is located on control board, the same is inside display module. This fault is the result of wrong interpretation of display module of logic level between two communication frames.
This technical conceived problem is appeared from August 2000.

Corrective action:

This failure has been resolved by a modification of two values of resistors inside the display module.
The revision levels become:
· A20, B20 for the ATV58 display modules.
· A02 for the ATV58Fdisplay modules.

This evolution is applied from the week 47/2000 on all manufactured PRODUCTS and all VW3A58101 spare parts.


Information for internal use:

We have noticed that anyway neither control board nor display module have never been directly to the fault origin . Fault "Err X" is always due to the association of two items.

On no account this failure cannot to disrupted the motor running but she can to disturb only the programming of product.

If during the programming, a customer encounters to " Err3 " or " Err7 " with a product manufactured from the week 31/00 to 46/00 , it is advised to exchange only the VW3A58101 display module.

This problem can also appear if the baudrate of internal communication was modified ( subD 9 pins ) and there is a difference between the keypad and internal modbus.

A solution is to reset the inverter with the 50/60 Hz switch to return the baudrate in factory setting, don't forget to accord the Twido PLC.

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