Chapter 3 Operation Series 780S Instruction Manual
3-12 IM-78S-B
Note: when adjusting zero the current signal will be driven to 4 mA and
when adjusting span the current signal will be driven to 20 mA. We recom-
mend recording the current values before making any changes to the current
zero or span settings.
Current Zero Adjustment
If needed, use Zero mA (Function 3) to adjust the 4-20 mA output to
4.0 mA.
1. Disconnect the 4-20 mA (+) loop wire. Set the DVM to current
mode and connect the positive lead to the wire you just discon-
nected. Connect the negative lead to the 4-20 mA (–) on the flow
meter terminal block.
2. Select FUNCTION, enter the password (if so equipped). Select
FUNCTION again until Zero mA appears on the LCD display or a
solid “3” appears on the LED. Adjust UP or DOWN until the DVM
indicates between 3.95 and 4.05 mA. Set DVM back to voltage
mode when adjustment is complete.
3. After 12 seconds of non-activity, the meter returns to the Run
Mode and the new parameter is in effect.
Current Span Adjustment
If needed, use Span mA (Function 4) to adjust the 4-20 mA output
to 20.0 mA.
1. Disconnect the 4-20 mA (+) loop wire. Set the DVM to current
mode and connect the positive lead to the wire you just discon-
nected. Connect the negative lead to 4-20 (–) on the flow meter
terminal block.
2. Select FUNCTION, enter the password (if so equipped). Select
FUNCTION again until Span mA appears on the LCD display or a
solid “4” appears on the LED. Adjust UP or DOWN 2 until the
DVM indicates between 19.95 and 20.05 mA. Set DVM back to
voltage mode when adjustment is complete.
3. After 12 seconds of non-activity, the meter returns to the Run
Mode and the new parameter is in effect.
Caution!
Adjusting zero or span will
affect meter calibration.
