Specifications

D1500 Data Sheet D-2
Figure D-1 Bridge Circuit Wiring
To perform an initial offset trim, attach the bridge unit to the module (as
shown in Figure 1). Clear out any previous offset trims with the Clear Zero
(CZ) command. Apply the desired zero condition to the bridge sensor. For
a Strain Gage Bridge this would be the relaxed or unstrained condition. For
load cells, the zero condition could include any tare weight due to a weighing
platform or other attachments that would affect the zero balance. Obtain an
initial reading using the Read Data (RD) command. The output data will
indicate the total offset of the system. Subtract the offset value from the
usable input range of your module, either ±60mV or ±120mV. The result is
the maximum usable “input overhead”. If the overhead is not sufficient for
your application, the bridge must be trimmed externally to lower the offset
to an acceptable value. The bridge may be trimmed with a small series
resistance or a large shunt resistance to the appropriate leg of the bridge (as
shown is Figure 2). If the initial offset is acceptable, the offset may be
trimmed with the Trim Zero (TZ) command.