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Getting Started with the Model DMD-476
1. Excitation Supply. If remote sensing is not used, connect +Sense to +Excitation, terminal 3 to 4, and
connect -Sense to -Excitation, terminal 1 to 2.
2. Apply power to the DMD-476 and adjust the Excitation supply. Turn SWB-1 "ON" for a fixed 10 Volts.
This will set the supply to 10.2 ±2.5% and provide the best temperature stability. For voltages between
5 and 10 Volts, place SWB-1 in the "OFF" position and set the Excitation Supply with potentiometer
E. SWB-2 may be in either position.
3. Turn the power to the DMD-476 off and connect the load cell to the DMD-476 Excitation terminals and
the Amplifier Inputs.
4. Turn on power to the DMD-476.
5. Turn SWA-3 "ON". (To set output ZERO current with pot D.)
6. Select the expected full scale signal range according to the table with SWA-4 and
SWA-5. If the output from the load cell is not known, set both SW-4 and
SW-5 "ON" for the 40-50mV range.
7. Set SWA-2 "OFF" for 4mA or SWA-2 "ON" for 0mA output ZERO.
8. Adjust D potentiometer for desired ZERO current.
9. Turn SWA-3 "OFF". Expect output current to change.
10. Apply no load or dead weight to load cell.
11. Adjust TARE potentiometers A and B for the same ZERO current set in Step 8.
SWA-1 "OFF" provides a bridge output balance of -3mV to +15mV, and "ON" between +15mV and
+25mV.
12. Apply full scale load and adjust SPAN (GAIN) potentiometer C for the desired full scale output current.
Set Range switches SWA-4 and SWA-5 as required.
13. Remove full scale load and check ZERO output current. Adjust FINE TARE potentiometer A if required.
14. Recheck full scale as in Step 12.
15. End.
Note: If the amplifier is used without using the DMD-476 Excitation Supply, the external power supply low
side must be connected to the -EXCITATION terminal 2 on the Model DMD-476, or one of the inputs
must be tied to terminal 2, -EXCITATION. This provides a DC return path for the finite amplifier input
current.
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