Hach ORBISPHERE 32301 Basic User Manual page 10

If it is, then the tests allow you to localize the problem and report it to your Hach Lange
representative for repair. If it is not, then you know that the problem is of chemical or mechanical
origin and should act accordingly. Chemical problems may merely necessitate a very thorough
sensor service. Mechanical problems might take the form of poor connections on the inlet side of the
sample pipework.
For these tests it is not necessary to plug the sensor cleaning and regeneration center into the power
supply.
Please carry out the tests in the order in which they are presented here. Ignore any instructions
which do not apply to your system.
Sensor testing
For sensor testing you will require an ohmmeter with leads ending in banana plugs suitable to be
plugged into the group of eleven sockets on the TEST panel of the sensor cleaning and regeneration
center. Two such banana plugs are supplied with each unit.
Figure 5 LEMO-10 plug
The numbers on these sockets correspond to the pin numbers on a LEMO-10 sensor plug as
illustrated in Figure 5.
The cleaning and regeneration center does not need to be plugged into the power for these tests.
The LEMO plug of the sensor being tested must be plugged into the socket in the center of the unit
(No. 6 in Figure 1 on page 5).
Check temperature measurement thermistors
Checking the values against those given in
the resistance between:
A discrepancy greater than ±10% indicates a probable fault in the circuit.
Check temperature compensation thermistors (model 31331 only)
Checking the values against those given in
the resistance between:
A discrepancy greater than ±10% indicates a probable fault in the circuit.
Check connections within the sensor
Measure the resistance between all pins and the shield. Check that no short circuits exist in the
sensor by measuring between the following pins:
10 English
Resistance tables
All sensors
Pin 3 and Pin 6
Resistance tables
Ozone sensor (model 31331 only)
Pin 7 and Pin 8
Pin 2 and Pin 5
on page 11, if applicable, measure
on page 11, if applicable, measure