34
tina88e1 (2014-01)
The <ERROR> LED will continue blinking red after 8 s if
•
the signal output is negative (< -20 mV) when the final pres-
sure has been attained
•
the zero adjustment has failed.
4.4.2
<
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 diagnostic port (
→
[3]),
•
the RS232 interface (
→
[2], [3]),
•
the Ethernet interface (
→
[1]),
•
the wireless network (
→
[4], [5]).
Operate the gauge for at least 90 minutes 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 <ERROR> 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.
