Its about 4am here so i'm getting hazzy...
When I said element offset I meant the radio button in classiclader's modbus configuration page - it's either 0 or 1
anyways the command send seems ok but is different from your program - if I'm reading it right:
your program 0103210000018e36 broken up is 01 03 2100 0001 8e36
meaning slave 1, function 3, address 2100H, number of bytes 1, then checksome
from classicladder:
Code:
INFO CLASSICLADDER- Modbus I/O module to send: Lgt=8 <- Slave address-1 Function code-3 Data-8 34 0 1 C7 A4
meaning slave 1, function 3, address 0834H, number of bytes 1, then checksome
oh wait - in classic ladder the '1st modbus element' must be input as a decimal 8448 - not 2100
In my test config then the message is the same as your program:
Code:
INFO CLASSICLADDER- Modbus I/O module to send: Lgt=8 <- Slave address-1 Function code-3 Data-21 0 0 1 8E 36
That looks better...
