Sierra FLAT-TRAKTM 780S - Manual (Page 37)

Series 780S Instruction Manual Chapter 3 Operation
IM-78S-B 3-11
Using the Smart Electronics Advanced Features
Zero and span (Function 1 through 4) can be used to validate system
operation and calibrate the digital to analog signals on the Smart
electronics device. Additionally, these functions can compensate for
resistance in long signal cables connected to your data collection or
indicating system.
You must use a certified digital voltmeter to adjust zero and span as
the voltmeter acts as a standard. We recommend recording the current
values as shown on the LCD display or DVM before making any
changes to the zero and span settings. Note: when adjusting zero the
voltage signal will be driven to 0 VDC and when adjusting span the
voltage signal will be driven to 5 VDC (or 10 VDC).
Voltage Zero Adjustment
If needed, use Zero Volts (Function 1) to adjust the 0-5 VDC output
to 0.0 VDC, or optional 0-10 VDC to 0.0 VDC.
1. Set the DVM to voltage mode and connect between Vout+ and
Vout–.
2. Select FUNCTION, enter the password (if so equipped). Select
FUNCTION again until Zero Volts appears on the LCD display
or a solid “1” appears on the LED. Adjust UP or DOWN until
the DVM indicates between 0 and .01 VDC (no less than 0.005,
the Smart electronics device cannot drive negative values).
3. After 12 seconds of non-activity, the meter returns to the Run
Mode and the new parameter is in effect.
Voltage Span Adjustment
If needed, use Span Volts (Function 2) to adjust the 0-5 VDC output
to 5.0 VDC, or optional 0-10 VDC to 10 VDC.
1. Set the DVM to voltage mode and connect between Vout+ and Vout–.
2. Select FUNCTION, enter the password (if so equipped). Select
FUNCTION again until Span Volts appears on the LCD display or
a solid “2” appears on the LED. Adjust UP or DOWN until the
DVM, indicates between 4.99 and 5.01 VDC. (For 0-10 VDC de-
vices, the target value is 9.99 to 10.01.)
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.