Siemens SIWAREX WP251 Manual page 190

Communication with SIMATIC S7-1200
11.1 Integration in SIMATIC S7-1200
A summary of all existing command codes can be found in chapter →Command lists
(Page 179).
The following equation for generation of a corresponding command code applies to the
reading of data records from the SIWAREX to the data block:
Command code = 2000 + X
The following equation for generation of a corresponding command code applies to the
writing of data records from the data block to the SIWAREX:
Command code = 4000 + X
Example
The following example clarifies the actions with command mailboxes and data records:
"Calibration weight 1" is to be set to a value of 12.5 from the CPU. Since "Calibration weight
1" is a parameter of data record 3 (see section → Scale parameters and functions
(Page 57)), service mode must first be activated. This is possible using command code "1"
(see section → Command lists (Page 179)).
The variable "i_CMD_CODE" must therefore be assigned the value "1" and the associated
"bo_CMD_TRIGGER" set to TRUE. Subsequently, the module is directly in service mode
(DIAG LED flashes green):
i_CMD_CODE = 1
bo_CMD_TRIGGER = TRUE
Since only complete data records can be read or written, it is recommendable to now read
data record 3 into the CPU. This is carried out using command code 2003 (see chapter →
Command lists (Page 179)):
i_CMD_CODE = 2003
bo_CMD_TRIGGER = TRUE
All current data from data record 3 are now present in the data block. The calibration weight
is then set as desired to a value of 12.5:
CALIB_WEIGHT_1 = 12.5
The modified data record 3 must now be written into the SIWAREX again. This is carried out
using command code 4003 (see chapter → Command lists (Page 179)):
i_CMD_CODE = 4003
bo_CMD_TRIGGER = TRUE
The new calibration weight is now present in the SIWAREX and can be used. Service mode
for the module should subsequently be switched off again using command "2".
This procedure for reading and writing data records is identical for all data records.
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(X = desired data record number)
(X = desired data record number)
SIWAREX WP251
Manual, 12/2015, A5E37203357A