Hello,

When I try to establish a Modbus TCP connection, my status gets the value 16#80B7. I know that it means "Error in one of the following parameters of UDT65: block_length, local_tsap_id_len, rem_subnet_id_len, rem_staddr_len, rem_tsap_id_len or next_staddr_len". Attached you'll see the actual values for my connection. My guess, the problem is with the block_length (length of the UDT (64bytes)). My actual value is W#16#0340 and not W#16#040 (64 bytes in dec). How could I change the value of block_length from W#16#0340 to W#16#040?

Many thanks in advance!

Kaulquappe

Hello jhonut,
the block length must be 40H. I think you modified it by mistake, either with your program or with the editor.

Regards,
Kaulquappe

 Hello, Kaulquappe

If I try to change the value in DB1, it is overwritten to W#16#0340. I really have no idea what I did to get this value. And neither how to restore to W#16#040. In UDT65 the initial value is W#16#040 but i can't go online to see the actual value and modify it. Any idea how could I get back to W#16#040?

Thanks for replying! 

smiffy

If it is being overwritten, then the only possible way I can think of is that it is your code somewhere that is doing so. Used the cross reference to search for that DB and see what destructive references you can find. That might throw up the guilty party.

 Hello, smiffy

I have searched "block_length" (DB1.DBW0) using cross reference, but it's not used in the rest of the program. This is what confuses me the most.

Is there a way to search, through my program, for the value W#16#0340?   

Thanks for replying!

Kaulquappe

Just an addendum to Smiffy's post:
Or change the DB number - but nevertheless you should look for your programming error.

 Hello, Kaulquappe

But the values of the DB are loaded from UDT65. When I open the UDT, the intial value of "block_length" is W#16#40. Is posible that UDT to load another value than intial one?

Thanks for replying!

Kaulquappe

I would check it the other way round: rename DB1 and adapt the pointer when calling TCON.

 What do you mean by "adapt the pointer"?