Rockwell Automation 937CU-AISTR-DC1 Strain Gauge Converter Installation Instructions - Manual (Page 45)

Trigger inputs
One trigger input must be
parameterized as "Tare" to enable a subsequent zero point setup.
Calibration
The calibration can be carried out offline or online.
Offline
Calibration without mechanical load is the simplest way of calibrating the
Strain Gauge Converter.
However, inaccuracies are to be expected because the whole measuring chain is not included in the
calibration process.
With an empty weighing device setting a zero point for the whole system is possible via the input
parameterized as tare under "Trigger input". The characteristic of the weighing cell is retained and
only the origin is adjusted.
The
Strain Gauge Converter is then calibrated. Because the measuring cells are normally calibrated
at factory and are very strongly linear, the measuring values are calculated with great accuracy.
Online
The online calibration is more accurate than the offline calibration because it involves the whole
measuring chain 100%. The measuring cell is put under a defined load and the
Strain Gauge
Converter calibrated to these points.
The cell returns with an empty weighing platform 1.43
mV. In the menu item Input > Calibration >
Adjust > Zero point > Execute a zero point calibration is carried out, i.
e. the 1.43 mV are allocated
to 0
kg which is now also displayed by the Strain Gauge Converter.
A defined weight must then be placed on the cell, e. g. 5 t.
Under the menu item Input > Calibration > Adjust > Weight the applied weight must now be entered
(5
t) and the calibration be carried out via Execute. The Strain Gauge Converter now displays 5 t.
The processes Zero point calibration and Adjust must always be carried out together, but the
sequence described above does not have to be adhered to (it is possible to calibrate Adjust and then
Zero point.
Bul. 937
C Strain Gauge Converter Installation Instructions
43