Hi to everyone,
I got an AB7000-C back-up from a client, asking to add some modbus command for the same slave.
Currently, the module it’s working properly, in fact i’m able to read the valus from my S7 400 (as a master profibus), but there is something i don’t understand.
For all the response arriving from the modbus slave, it’s been reserved an amount of memory bigger than the necessary. for example:
01-03-1c-e9-00-0f (15 registers, from reg 7401, it means 30 bytes).
byte count 3c (60 bytes)
Data length 3c (60 bytes)
Data location 00 (from the first byte of the internal memory.
I can assume that, ok the master reads 30 bytes, but stores them into 60, so from 0 to 29 there are my values and from 30 to 59 are empty.
So, why if i try to replace the same configuration at the workshop it doesnt work?
if i try to store 30 bytes into 60 like the original doesn’t work, if i put 30 bytes into the same amount then works.
I dont understand what i’m missing.
Thanks for any advice.