SIWAREX MS is a compact weighing module for SIMATIC Automation System S7-200.
Main applications are bin scales, weighbridges, crane scales, force and tightening torque
measuring.
Purpose of this document for functional safety
This programming manual contains all information that you will require to commission and
use the device.
It is aimed at persons who install the device mechanically, connect it electrically,
parameterize and commission it, as well as at service and maintenance engineers.
Notes on warranty
The contents of this programming manual shall not become part of or modify any prior or
existing agreement, commitment or legal relationship. All obligations on the part of
Siemens AG are contained in the respective sales contract, which also contains the
complete and solely applicable warranty conditions. Any statements on the device
versions described in the programming manual do not create new warranties or modify the
existing warranty.
The content reflects the technical status at the time of printing. We reserve the right to
make technical changes in the course of further development.
Validation of this document
This documentation is only valid in conjunction with the manual SIWAREX MS. This
manual is available on the Siemens homepage.
Following hardware parts and software are requested to integrate a scale into SIMATIC
S7-200: SIWAREX MS module, 24V Power Module, S7-200 CPU, SIWATOOL MS
configuration package, RS232 cable, computer with Windows XP or higher and a
calibration weight bigger than 5% of the sum of the nominal value of all load cells.
24V Power Supply SIMATIC CPU S7-200 SIWAREX MS
7MH4930-0AA01
The decimal point is not part of the integer-value and is only used for the Siwatool-display
g
(and a remote display, if available).
That means the numeral step and the decimal point have to determine, so that the
displayed weight value (weight value = integer-value) will not increase the value of
32767.
Characteristic Value:
Characteristic value of the load cell.
The specification of the characteristic value can be read into the techincal data sheet of
the load cell.
Limit frequence:
If this parameter is set to 5 Hz, the scale will respond quickly to a weight change; if it is set
to 0.05 Hz, the scale will “move slowly”.
Step response of the limit frequence of 2 Hz:
Critical dampin
Depth of average value filter:
The average value filter ensures a stable weight value and prevents interference.
The weight is measured according to the average value of n weight values.
If n = 10, 10 weight values will be used for calculating the average value. The earliest
value is discarded every 20 milliseconds and the latest value will be added for the
calculation.
Standstill range and Standstill time:
Standstill range and Standstill time (in msec) are used to monitor when the scale has
stand still.
If the weight change is lower than the specified range (standstill range) within the specified
period (standstill time) the scale stands still.
The monitoring of the scale standstill is used e.g. for the commands “zeroing” or “taring”.
Neg. zeroing range %, Pos. zeroing range % and Weighing range:
By executing the command “zeroing” the weight value is set to zero. With the parameters
“Neg. zeroing range %” and “Pos. zeroing range %” the zeroing range is defined. The
values are set as percent of the parameter “Weighing range”.
The parameter “Weighing range” is the maximum of material, which will put on the scale.
For example (see also the picture above):
The zeroing range is between -20 kg (-1% of 2000) and +60 kg (+3% of 2000).
Zeroing will be rejected if the current gross weight is too high or too low.
After setting the parameters, click Send to send the changed parameters to the Siwarex
MS module:
Afterwards, place the adjustment weight on the scale and execute the command
Adjustment weight 1 valid (4). With executing of this command, the adjustment line is
detected of the scale.
The Siwarex MS module shows now the adjustment weight.
5. Adjustment without an adjustment
weight (theoretical adjustment)
If the adjustment is not possible by using adjustment weights, the scale can also be
adjusted without adjustment weights, if the mechanical structure of the scale is correct.
If the measuring logs are available, these logs can be used for the theoretical adjustment.
If the measuring logs aren’t available, the default-values of the load cells can be used of
the technical data sheet.
The execution of the theoretical adjustment is handled with the help of the SIWATOOL MS
software.
First, the "Characteristic value" (e.g. “2 mV/V”) must be defined in the DR3, index card:
"Calibration":
Then, switch to the "Theoret. Calib." index card.
To execute the theoretical adjustment, the rated load for all load cells is defined first,
e.g. 3 load cells with 1,000 kg each result in a rated load of 3,000 kg.
(See also step “1.” in the picture below)
The “Zero offset in uV/V” (unit = μV/V), and the “Characteristic value” (unit = mV/V) is then
entered for each individual load cell.
(See also step “2.” and “3.” in the picture below)
These values are taken from the respective load cell measuring log.
If the measuring logs aren’t available, the default-values can be used,
e.g. “Zero offset in uV/V” = “0” and “Characteristic value” = “2.0”:
After entering the data for each load cell, the adjustment digits are calculated and
the result is displayed by actuating the button "Calculate adj. Digits".
Then, the calculated adjustment digits can be integrated into the DR3 by actuating the
button "Accept calculation":
1. 2.
The DR3 is then sent to the weight module with the new adjustment data with the button
"Send":
All rights reserved by Siemens AG
This document is subject to change without notice. Under no circumstances
shall the content of this document be construed as an express or implied
promise, guarantee (for any method, product or equipment) or implication by or
from Siemens AG. Partial or full replication or translation of this document
without written permission from Siemens AG is illegal.