aran_v02 or higher
NRF-100_KM Rev. : 1.0
16 / 04 / 2002
01 / 12 / 2002
OFFSET and RESET functions (or values ) are factory
set. They may have to be changed by the customer in
special cases only. Follow the procedures below.
There may seem to be a malfunction with the transmitter
when the 4-20mA power loop is activated for the first
time. The mA reading may be below 4mA or above
20mA and pressing the Z and S push buttons does not
change the output.
Note : Push button may have to be depressed for up to
a minute before the value changes.
An OFFSET function may have to be performed. To
re-OFFSET the transmitter, lower the level in the tank to
below the probe. Press Z UP and S UP push buttons at
the same time,then release in 1 or 2 seconds. The trans-
mitter will now show a default value close to 4mA.
In very rare cases, a problem of calibration still may
persist. This is because the values of the minimum and
maximum are not properly distributed. The RESET
function may have to be perfomed To RESET the
transmitter, simply press Z DW and S DW push buttons
at the same time,then release the two push buttons after
1 or 2 seconds. Then re-OFFSET the transmitter as per
instructions above. The transmitter will now show a
default value close to 4mA.
Note: When you RESET the transmitter, always perform
the OFFSET after the RESET.
This feature, primarily designed for agitated tanks and
factory set at 0 sec. (max. CW, neg. direction) via a
single turn pot, sets a time delay on the output signal.
The time delay range is 0-10 sec. approx. For non-
agitated tanks a zero setting is fine. Increase the setting
for agitated tanks by turning the pot CCW. This stabilizes
the mA reading, but adds time delay. When performing
calibration, always set pot to maximum CW direction
( minimum time delay).
Turn the DAMP ADJ pot to max CW (neg.) direction.
1.
Fill the tank to its L (0% ) level (with probe covered).
2.
Depress UP or DW buttons on Z until meter reads
4.00mA. Do not change the zero controls from now
on. If changed, the material will have to be returned
to the L ( 0%) level.
Note: If a 4.00mA value cannot be reached, then perform
OFFSET AND RESET functions
3.
Fill the tank to the desired H ( 100 % ) level.
Note: The loop current may not rise in proportion to the
rising material level in tank. Instead it may ris more rapidly
or more slowly than the material level. The span, S, U P o r
D W buttons may be used occasionally to maintain the loop
current approximatelly proportional to the tank filling or just
below the 20.00 mA reading.
4 .
After the tank has been filled to H (100%), depress
SPAN UP or D W buttons as required to obtain a meter
reading of 20.00 mA. If 20.00 mA reading has been
obtained, the calibration is complete.
Note: If a 20.00mA value cannot be reached, then
peform OFFSET AND RESET functions and re-start the
calibration
Fig. 4
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