Sending data area for initial setting
Parameter table for the sending data area (s+9, s+A) is as follows.
Figure 6.53 Sending data area format (Modbus slave / Initial setting)
Meaning of each parameter described as follows.
[1] Number of send data (bytes)
The number of data transmitted to EH-SIO is specified.
The number of transmission data changes with setup of I/O mapping information. When you do not use I/O
mapping (use default setting), the number of transmission data should set to 10 bytes (10 / H000A).
« Note »
Software ver. 1.0 are not supporting the I/O mapping function. Since the setting parameter in software ver. 1.0 is
10 word fixation.
[2] Communication mode
In case of modbus slave mode, please set H0011 or H0111.
« Note »
Target internal output of function code 06 can be selected from “WM” and “WR” since software ver. 3.0 or
newer. When target internal output is “WM” as same as the operation of software ver. 2.6 or before, please set
H0011. When target internal output is “WR”, please set H0111.
[3] Modbus communication mode
Select modbus ASCII mode or RTU mode.
Table 6.16 Modbus communication mode
Function code 03, 06, 16 in Modbus protocol is the function code for accessing to “holding register”.
However, in case of EH-SIO (software ver. 2.6 or before), function code 03 and 06 is for accessing to “WR”, and
function code 06 is for accessing to “WM”. In this case, if Modbus master accesses internal output by using
function code 03 and 06, Modbus master cannot read a value which write by oneself.
If you want to treat “WR” as holding register, please select the target internal output of function code 06 to “WR”.
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