4.5 Refill sensor with electrolyte and replace membrane
Once servicing is complete prepare the sensor for reuse.
1. Install a new membrane and electrolyte to the sensor. Refer to the operator manual delivered with
the sensor for details on how to do this.
2. Rinse excess electrolyte off the sensor with water.
3. The sensor can now be calibrated and returned to service.
Section 5 Circuit testing functions
This part of the manual describes a series of tests which will allow you to check if the electronics of
your sensor are functioning correctly.
The cause of such problems may be chemical, electronic or mechanical in origin. Since the tests
described here are logical, quick and simple to carry out, you can rapidly discover whether or not a
particular problem is of electronic origin or not.
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.
5.1 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).
5.1.1 Check temperature measurement thermistors
Checking the values against those given in
Resistance tables
on page 11, if applicable, measure
the resistance between:
All sensors
Pin 3 and Pin 6
A discrepancy greater than ±10% indicates a probable fault in the circuit.
10 English