Need help on Danfoss MCT10 connecting to VLT2800

[kkzhsps]

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I have VLT2800 which needs replacement. I have installed MCT10 V3.17 and RS485 driver to connect to VLT2800 to dump its configuration data.
Have checked that VFD parameters are as follows:
500 [1] Address = 1
501 [5] baud rate = 9600
512 [1] FC telegram
561 [0] FC protocol
Tried terminals 68, 69 and Sub-D connector pins 8, 9 subsequently but no response.
Have monitored the serial com and found out that the VLT2800 gave no response to the MCT10 queries.
Is there any parameter or any setup that prevent me from getting normal communication with MCT10?
MCT10 gave "Communication errors (125)" every time after scanning for some time.
Please help.
Thank you.

 

[thomass5]

Which adapter for RS485 / RS232 do you use?

 

[kkzhsps]

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A Chinese RS232-to-RS485 adapter using COM 1 on a Dell D520 laptop.
I could monitor the serial com with a serial com monitoring device.
There was no answer from the VLT 2800. It happened on both the old and new VLT 2800.
I suspected there should be something related to the parameters setup or even the operating mode of VLT 2800.
Attached is the com dialog com text recorded.

 

[thomass5]

Which Parameers do you have on de PC for the Communication? Have you the Manual for the Adapter? Wich cabel you use for the link from PC to Adapter?

 

[kkzhsps]

Solved. Thanks a lot.
I have mistaken the RS232-to-422/485 convertor as the old fashion one in which one has to tied up the (TXD+, RXD+) and (TXD-, RXD-) together to get RS485. The new fashion one that I used just needed T/RXD+ and T/RXD- for the A,B lines of RS485.