Cw - Automatic Check Weigher; Dr03 Calibration Parameters; Overview - Siemens SIMATIC ET 200SP Operating Instructions Manual

Parameter assignment/addressing

6.5 DR03 Calibration parameters

6.4.6

CW - Automatic check weigher

You set the CW weighing operating mode in data record 3. The CW weighing operating mode
enables you to implement a static automatic checkweigher with the electronic weighing system.
Test objects are checked for a default set point; tolerance bits are set when the value is below
or above the set point so that the PLC can sort accordingly.
If you want a legal-for-trade check with the electronic weighing system, it must be performed
statically (at stability 2). Static means that the test object is not tested dynamically during
throughput. In case of a conveyor belt, a static, legal-for-trade check means that the weighing
belt must be briefly stopped to perform the check. For checkweighers that are not legal-for-
trade, the check can be made dynamically.
The electronic weighing system offers two options for checking:
1. Start manually triggered check with command 1101 (single weighing).
The electronic weighing system waits in weighing step 0 for a command from the PLC/user.
When the command xyz is sent to the electronic weighing system, the command jumps
directly to weighing step 4 and waits for stability 2 (defined in DR 3). As soon as stability 2
has been reached, the current weight is measured and compared to the specified set point
(DR 20). According to the tolerance settings in DR 22, corresponding tolerance feedback
messages are made available by the electronic weighing system. The result is forwarded to
the module-internal statistics (DR 39) and updated.
2. Start automatic continuous operation with command 1103 (continuous operation)
After the command is triggered, the electronic weighing system waits in weighing step 0 until
limit 3 (DR 6) is exceeded. As soon as the actual weight exceeds this threshold, the
electronic weighing system automatically jumps to weighing step 4 and waits for stability 2.
As soon as stability 2 has been reached, the current weight is measured and compared to
the specified set point (DR 20). According to the tolerance settings in DR 22, corresponding
tolerance feedback messages are made available by the electronic weighing system. The
result is forwarded to the module-internal statistics (DR 39) and updated. Subsequently,
limit 3 must be undershot again (discharging the test object) so that the electronic weighing
system automatically jumps back to weighing step 0 and waits until the limit is exceeded
once again. You can exit continuous operation at any time with command 1123 (Stop
continuous mode).
6.5 DR03 Calibration parameters
6.5.1

Overview

Data record DR03 summarizes the basic parameters of non-automatic scales. You can only
transfer the parameters during active service mode of the electronic weighing system. You can
read the DRs into the interface DB at any time.
DR03 contains the following parameters for the characteristic curve, for example:
● Calibration weight
● Calibration digits
● Stability parameters
● Tare and zeroing / zero setting options
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Technology module TM SIWAREX WP351 HF
Operating Instructions, 01/2020, A5E47521010-AA