
Instruction Manual
ExTox Transmitter NH3-20-IS
Page 9 of 15
6 Adjustment
On site a complete adjustment is only possible with limitations. The electrode of the NH3-20-
IS needs a long running-in time in the medium until a balanced condition is finally reached.
When applying test solutions it is inevitable to take the electrode out of the measuring adapter
and with this to disturb the balanced condition. After finishing the adjustment and rebuilding
the electrode into the measuring adapter a drifting of the zero point can be observed for up
to two days. Due to this two adjustment procedures are described hereafter.
6.1 Manual Adjustment without Calibration
We recommend this procedure for slight corrections which could occur due to displacements
of the zero point position. These influences occur due to changes of the medium / ambient
temperature or the composition of the sole, for example adding an additive. On this, only
displacements of few ppm below the alarm level can be observed. In case the alarm level is
reached or in case of bigger deviations this procedure should not be performed before an
ammonia leakage or damage of the electrode could be excluded:
1. Release service mode (see 4.1). On successful release the green Power-LED changes from
permanent light to blinking light.
2. Press the key "MODE" as often until UL=xxxx (xxxx=Measured value) is indicated.
3. Note the indicated value (typically between 1900 and 2400).
4. In case one or more of the following states are recognized, it has to be checked via the
ammonia test set whether the sole is free from ammonia by means of a probe.
UL out of the above mentioned typical range
NH3-20-IS is in over-scale of measuring range
NH3-20-IS indicates values above 15 ppm.
In case the sole is free from ammonia, it is a malfunction of the electrode. In this case the
electrode has to be checked and maintained or changed. Only after running in phase of
the electrode the re-check can be done again (starting again with Step 1).
In case the sole is not free from ammonia, the electrode works correctly. Adjustment
should not be changed. (Stop of adjustment).
5. Press the keys "^" and "v" simultaneously, ULm=xxxx is indicated.
6. Set the value which has been noted under 3. by means of the keys "^" and "v".
7. Press the key "CR"; "SAVE" is indicated for a short time.
8. Press the key „MODE“ as often until UH=xxxx is indicated.
9. Press the keys "^" and "v" simultaneously; UHm=xxxx is indicated.
10. Add 400 to the value noted under 3. and enter the result by means of the keys "^" and
"v".
Remark: The value 400 states the throw of the electrode. The value has been chosen so
safety related that alarming in time is ensured.
11. Press the key "CR"; "SAVE" is indicated for a short time.
12. Lock the Service Mode (see 4.1). After successful locking the green Power-LED changes
from blinking light to permanent light.