Nor-Cal CDG 160 OP Lit - Manual (Page 25)

CDG160-OP-LIT (2010-06) 25
After zero adjustment, the gauge automatically returns
to the measurement mode.
The <STATUS> LED blinks green if
• the signal output is negative (< -20 mV) when the final pres-
sure has been attained
• the zero adjustment has failed.
4.2.2
<ZERO> Adjustment with Ramp Function
The ramp function allows to adjust the zero at a known reference
pressure within the measurement range of the gauge.
It also permits to adjust an offset of the characteristic curve in
order to
• compensate for the offset of the measuring system or
• obtain a slightly positive zero for a 0 … 10 V AD converter.
The offset should not exceed 2% of the F.S. (+200 mV). At a
higher positive offset, the upper limit of the measurement range
is exceeded.
Zero adjustment using the ramp function can be
performed via
• the <ZERO> button on the gauge,
• the RS232C interface (→  [1]).
Recommended procedure for adjusting the offset of a
measuring system:
→ Notice  23.

Operate the gauge for at least 2 hours under constant
ambient conditions (until the signal is stable).

Push the <ZERO> button with a pin (max. ø1.1 mm) and
keep it depressed. The <STATUS> LED starts blinking.
After 5 s, the zero adjustment value, starting at the current
output value, keeps continually changing (ramp) until the
button is released or until the setting limit (max. 25% F.S.)
is reached. The corresponding output signal is delayed by
about 1 s.