Communication
11.2 Communication via Modbus
SIWAREX WP231
Manual, 07/2014, A5E31238908A-02
155
Table 11- 5 Command mailbox 2: Average priority
Variable
Note
Type
Modbus registers
CMD2_CODE
Code of command to be executed
USHORT
920
CMD2_TRIGGER
Trigger for starting the command
USHORT
921
CMD2_STATUS
0=job running; 1=job finished (1 cycle)
USHORT
922
CMD2_QUIT
0=no error; <>0=error code
USHORT
923
Table 11- 6 Command mailbox 3: Low priority
Variable
Note
Type
Modbus registers
CMD3_CODE
Code of command to be executed
USHORT
930
CMD3_TRIGGER
Trigger for starting the command
USHORT
931
CMD3_STATUS
0=job running; 1=job finished (1 cycle)
USHORT
932
CMD3_QUIT
0=no error; <>0=error code
USHORT
933
11.2.1.4
Reading registers
The method for reading registers depends on whether they belong to the writable data
records (DR 3 to DR 29) or can only be read as current values (DR 30 to DR 34).
If you wish to read the registers from the data records DR 3 to DR 29, you must first export
these as a complete data record to the internal output buffer.
All Modbus registers of the individual parameters can be found in chapter
parameters and functions (Page 63).
Example
A parameter is to be read from data record 3 (DR 3).
●
First, write register CMD3_CODE with 2003 (2000 plus the number of the data record =
read data record).
●
Then write CMD3_TRIGGER with "1". The DR3 is then updated in the Modbus buffer
memory.
●
It is now possible to read one or more registers with the corresponding variable(s). The
data consistency of the registers read at this time is guaranteed.
You can find all further command numbers in chapter
→
Command lists (Page 139).
Example
A current measured value is to be read out from DR 30.
⇒ The register can be directly requested because its c
ontents are automatically refreshed in
the SIWAREX module at the specified measuring rate of 100 Hz and are always available
up-to-date.
Summary of Contents for SIWAREX WP231
Page 16: ...Safety notes 2 1 General safety instructions SIWAREX WP231 16 Manual 07 2014 A5E31238908A 02 ...
Page 132: ......
Page 174: ...Technical data 13 3 Approvals SIWAREX WP231 174 Manual 07 2014 A5E31238908A 02 ...
Page 180: ...List of abbreviations SIWAREX WP231 180 Manual 07 2014 A5E31238908A 02 ...
Page 182: ...Index SIWAREX WP231 182 Manual 07 2014 A5E31238908A 02 ...