Weidmuller STG - Bridge measuring transducer - Handbuch (Seite 21)

1
SelectingtheTAREadjustmentrange
The TARE control can be bipolar if required. Set the jumpers on the
main board to give the appropriate adjustment range.
Outputsignalformatselection
There are three sets of jumpers on the main board.
•Factoryadjustments
Bridgeexcitationvoltageequalisationadjustment
A factory adjustment on the power supply board ensures that the
negative and positive output voltages are equal. To adjust:
1. Remove the top cover of the STG (screws marked A & B and the
equivalent on the right hand side).
. Connect up the instrument according to the table for calibration
(output multimeter not required).
. Adjust the voltage equalisation control (VR1) until the voltage across
test points TARE– and EX– is the same as the voltage between
TARE– and EX+.
CMRRoptimisationadjustment
The CMRR optimisation control minimises the sensitivity to 0 Hz
noise on the input signal. To adjust:
1. Remove the electronics from the housing.
. Short the input terminals (7 & 8) together.
. Apply a 10 V p/p 0 Hz AC signal between TARE – and the input
terminals (7 & 8).
4. Connect an oscilloscope across TARE – and TARE+.
. Adjust the CMRR control until the 0 Hz signal shown on the
oscilloscope is minimised.