Optek CONTROL 200, Instruction Manual, Page: 124 / 135

C200 S
OFTWARE
Instruction Manual C200 Part2 A1.doc optek Danulat GmbH • D-45356 Essen • Germany page 102
7.1.2 Calibration Fail Message or no Response to pH/Redox Changes
The majority of problems are associated with the electrodes and cabling. Replace the electrodes as an initial check –
refer to the appropriate instruction manual. It is also important that all program parameters have been entered correctly
and have not been altered inadvertently – see Section 5.1.
If the above checks do not resolve the fault:
a) Check that the analyzer responds to a millivolt input. Connect a pH simulator, such as Model 2410, to the transmitter
input; +ve to glass and –ve to reference – see Manual CONTROL 200 Part 1 - Hardware. Select the CONFIG.
SENSORS page and set the Probe Type to Redox or ORP. Check that the analyzer displays the correct values as
set on the simulator.
Note. A normal laboratory mV source is not suitable for use as a pH simulator.
Failure to respond to the input indicates a fault with the analyzer which must be returned to the Company for repair.
Correct response, but with incorrect readings, usually indicates a calibration problem. Recalibrate the analyzer as
detailed in Section 6.
b) Use the pH simulator to carry out an impedance check on the analyzer, i.e. glass to reference, glass to earth and
reference to earth – refer to simulator manual.
If the analyzer fails this test, check for moisture within the transmitter and in particular the terminal compartment. It is
vital that all evidence of moisture is removed with the use of a hot air drier.
c) Reconnect the electrode cable and connect the simulator to the electrode end of the cable. Repeat the procedures
a) and b) above. If the analyzer fails test b), check for moisture around the connections and check that the insulation
on the inner co-axial conductor is clean and that the graphite layer has been removed.
7.1.3 Checking the Temperature Input
Check the analyzer responds to a temperature input. Disconnect the
Pt100/Pt1000/Balco 3K leads and connect a suitable resistance box
directly to the analyzer inputs – see Manual Converter CONTROL
200, Part 1 - Hardware. Check the analyzer displays the correct
values as set on the resistance box – see Table.
Incorrect readings usually indicate an electrical calibration problem.
Re-calibrate the analyzer as detailed in Section 6.1.3.