Siemens SIWAREX WP251, Manual

Page: 108 / 220

Scale parameters and functions
8.18 DR18 Control digital outputs
SIWAREX WP251
108
Manual, 12/2015, A5E37203357A
Variable Note Type Length
(bytes)
Rw De-
fault
Min. Max. Modbus
registers
Reserve Reserve BIT 0 rw 0 0 1 1620.11
Reserve Reserve BIT 0 rw 0 0 1 1620.10
Reserve Reserve BIT 0 rw 0 0 1 1620.9
Transition 0 Transition for weighing step 0 BIT 0 rw 0 0 1 1620.8
Transition 1 Transition for weighing step 1 BIT 0 rw 0 0 1 1620.7
Transition 2 Transition for weighing step 2 BIT 0 rw 0 0 1 1620.6
Transition 3 Transition for weighing step 3 BIT 0 rw 0 0 1 1620.5
Transition 4 Transition for weighing step 4 BIT 0 rw 0 0 1 1620.4
Transition 5 Transition for weighing step 5 BIT 0 rw 0 0 1 1620.3
Transition 6 Transition for weighing step 6 BIT 0 rw 0 0 1 1620.2
Transition 7 Transition for weighing step 7 BIT 2 rw 0 0 1 1620.1
Reserve 1 Reserve USHORT 2 rw 0 - - 1621
8.18.2 Specification for digital outputs DQ.0, DQ.1, DQ.2, DQ.3
Digital outputs 0 to 3 can be controlled using data record 18 with this parameter. This
function can be used for commissioning purposes, for example.
8.18.3 Transitions for weighing steps 0 to 7
A set transition allows the execution of an individual weighing step to be prevented.
Example:
The transition for weighing step 2 is set. Once dosing starts, weighing step 1 is performed.
WP251 then jumps to weighing step 2 but does not execute it. Status bit "Step blocked" is
output in DR 30. Only when the "Transition for weighing step 2" bit is reset is step 2
performed (coarse and fine signal switching)
When the module is operated with an S7-1200 CPU, transitions should not be set using DR
18 because another transition WORD with identical function is available in the Simatic I/O of
the function block. The advantage of this WORD is that it transmits cyclically to WP251 and
thus does not require a data record transfer. The transition WORD in the I/O is explained in
more detail in section "Integration in SIMATIC".
As an alternative to setting transitions via software, the digital inputs of WP251 can also be
configured with transitions for the individual weighing steps. Thus, a 24 V DC signal can be
used to disable or enable individual weighing steps.