Omega manual Getting Started with the Model DMD-476

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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