Low Sensor Efficiency/Slow Sensor Cal. Or No Response To D.o. Changes; Checking The Temperature Input; High Sample Readings - ABB 9438 User Manual

...9 SIMPLE FAULT FINDING
9.2 Low Sensor Efficiency/Slow Sensor Cal. or no
Response to D.O. Changes
a) Check that the sample drains fully from flowcell. If the sample
does NOT drain fully check:
i) Operation of solenoid valve.
ii) Sample inlet flow rate does not exceed 400 ml min
maximum.
iii) Sample fluid paths are free flowing and clear of partial
blockages.
iv) Solenoid valve drain tube is not kinked, blocked,
excessively long, does no rise along its length.
v) Flow gauge is not blocked or dirty.
b) Replace the sensor (see Section 8.2.2) as an initial check. It
is also important that all program parameters have been set
correctly and have not been altered inadvertently – see
Section 7.
If the fault persists:
c) Carry out an electrical calibration as detailed in Section 7.6
and check that the instrument responds correctly to the
current input.
Failure to respond to the input usually indicates a fault with
the transmitter, which must be returned to the Company for
repair.
d) If the response in a) is correct, select the
set the current source to a value which gives an on-scale
D.O. reading on the transmitter. Make a note of the current
source setting and the D.O. reading. Reconnect the sensor
cable and connect the current source to the sensor end of
the cable. Set the same current value on the source and
check that the transmitter displays the noted reading in this
configuration.
If check a) is correct but check b) fails, check the cable
connections and condition. If the response for both checks is
correct, fit a new sensor and calibrate it.
30

9.3 Checking the Temperature Input

Check that the instrument responds to a temperature input.
Disconnect the PT1000 leads and connect a suitable resistance
box directly to the transmitter inputs – see Section 7.6. Check
that the transmitter displays the correct values as set on the
resistance box – see Table 9.2.
–1
Incorrect readings usually indicate an electrical calibration
problem. Recalibrate the instrument – see Section 7.6.

9.4 High Sample Readings

If the sample reading is higher than expected, the most likely
reason is air ingress into the main sample line.
Check and tighten ALL sample connections as it is possible to
have an air leak into the sample without sample leaking.
and
Operating Page
Table 9.2 Temperature Readings for Resistance Inputs
T e m p e a r u t e r n I p t u R e s
( ) C ()
0 1 0 0 0
1 0 1 0 3 9
2 0 1 0 7 9
3 0 1 1 1 6
4 0 1 1 5 5
5 0 1 1 9 4
6 0 1 2 3 2
7 0 1 2 7 0
8 0 1 3 0 8
9 0 1 3 4 7
1 0 0 1 3 8 5
1 3 0 5 . 1 5 0 0
s i a t n c e
0 .
0 .
3 .
7 .
4 .
0 .
4 .
7 .
9 .
0 .
0 .
0 .