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CHECKING THE INTEGRITY OF A GAMRY CELL CABLE:
Of all the components of a Gamry system, the cell cable is the one that is
constantly being flexed and exposed to corrosive environments. This test
may take a couple of minutes, but if it identifies a problem, it will be
time well spent. If the cell cable is determined to be faulty, this
can prempt a Potentiostat from coming back to Gamry for repair. This
presents the rare opportunity to save both time and money...especially for
our international users.
SYMPTOMS OF SUSPECT LEADS:
There are other reasons that you may see these specific symptoms, but here
is what you will encounter if the cell cable is damaged:
1. During the Calibration routine, your Potentiostat passes the early
internal adjustment tests, but fails the later "Applied Pstat" or "Applied
Gstat" tests. This could be a general cell cable problem. Make sure
the cell cable is firmly connected to the Potentiostat and the leads are
correctly attached to the appropriate version of the Universal Dummy Cell.
2. The Working Sense (blue) and Reference (white) leads are the two inputs
to the Potentiostat's electrometer. The electrometer is the
potential-measurement device. If the measurement of Potential (Vm) drifts
from the value you requested, the problem may lie with one of these two
leads. In particular, if the voltage measurement gets to +/-11 Volts,
there is a good chance one of these leads is damaged. Intentional
resistors are installed in both of these leads. Both the Working Sense and
Reference leads should measure ~ 260 Ohms.
3. The Working (green) lead is the electrode that measures the current in
the cell. You can suspect this lead is damaged, if your system always
measures 0 Amps of current. Measuring 0 Amps doesn't stress the
Potentiostat, so you will not see any overloaded data. All displayed
points will be blue. The Working Electrode lead should measure 0 Ohms.
4. The Counter (red) lead is the output of the Control Amplifier. The
Control Amplifier is the device that delivers the necessary current to
control the cell. If there is a break in the Counter Electrode lead, the
Control Amplifier will not be able to control the cell. Your data will be
displayed in the Framework with red markers and be accompanied by a "CA
OVLD" message. The Counter Electrode Lead should measure 0 Ohms.
5. Also, the Counter Sense and Ground leads should measure 0 Ohms.
Of course, if you have multiple cell cables (for a MultEchem or
Multiplexer), substituting a known good cell cable is the quickest test.
The following are tests for a broken lead, the more common occurance.
To test for a lead inadvertently shorted to its neighbor, you can test
resistance between each pin surrounding the correct pin and the correct
cell lead. Each surrounding pin should measure infinite resistance.
You will need a digital multimeter capable of measuring resistance (any
electronics shop should certainly have one).
The pin number is printed on the black section inside the connector beside
the base of the pin. You may need to angle it or use a flashlight to see
it.
DIAGNOSTIC CHECK OF A GAMRY SERIES G / PCI4 / PC4 / ECM8 CELL CABLE:
**Note the Working Sense and Reference leads should measure ~250-260 Ohms.
The Working and Counter leads should measure 0 Ohms.**
1. Disconnect the Cell Cable from the back of the PCI4 Potentiostat.
2. Set the Multimeter to read Resistance in Ohms.
3. Connect one terminal of the Multimeter to the Working Sense (blue)
lead....Connect the other end to Pin # 1. You should measure ~251 Ohms.
4. Connect one terminal of the Multimeter to the Reference (white)
lead....Connect the other end to Pin # 6. You should measure ~251 Ohms.
5. Connect one terminal of the Multimeter to the Working (green)
lead....Connect the other end to Pin # 3. You should measure 0 Ohms.
6. Connect one terminal of the Multimeter to the Counter (red)
lead....Connect the other end to Pin # 9. You should measure 0 Ohms.
A broken cell cable is indicated by a very high (infinite) resistance.
This indicates that the cell cable is damaged and needs to be replaced. We
do not repair cell cables.
There is a complete description in Table D-1 on Page 6-11 of the manual
http://www.gamry.com/Support/Manuals/V5/PCI4.pdf, which coordinates the
Pin/Lead combinations.
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