Command Mailboxes; Reading Registers - Siemens SIWAREX WP251 Manual

11.2.4

Command mailboxes

Corresponding command codes must be sent in order to execute commands and to read
and write data records in the Modbus buffer memories. These are described in more detail in
chapter → Command lists (Page 179). The following tables list the Modbus registers used to
process these commands:
Table 11- 3 Command mailbox 1: Highest priority
Variable
CMD1_CODE
CMD1_TRIGGER
CMD1_STATUS
CMD1_QUIT
Table 11- 4 Command mailbox 2: Average priority
Variable
CMD2_CODE
CMD2_TRIGGER
CMD2_STATUS
CMD2_QUIT
Table 11- 5 Command mailbox 3: Low priority
Variable
CMD3_CODE
CMD3_TRIGGER
CMD3_STATUS
CMD3_QUIT
11.2.5

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 39).
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 → Scale
parameters and functions (Page 57).
SIWAREX WP251
Manual, 12/2015, A5E37203357A
Note
Code of command to be executed
Trigger for starting the command
0=job running; 1=job finished (1 cycle)
0=no error; <>0=error code
Note
Code of command to be executed
Trigger for starting the command
0=job running; 1=job finished (1 cycle)
0=no error; <>0=error code
Note
Code of command to be executed
Trigger for starting the command
0=job running; 1=job finished (1 cycle)
0=no error; <>0=error code
Communication with SIMATIC S7-1200
11.2 Communication via Modbus
Type
USHORT
USHORT
USHORT
USHORT
Type
USHORT
USHORT
USHORT
USHORT
Type
USHORT
USHORT
USHORT
USHORT
Modbus registers
910
911
912
913
Modbus registers
920
921
922
923
Modbus registers
930
931
932
933
195