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Pin
Signal Name
1
Working Sense
2
WS Shield
3
Working Electrode
4
WE Shield
5
Ground
6
Ref Electrode
7
Ref Shield
8
Counter Sense
9
Counter Electrode
Aux A/D Input
This input allows you to measure an externally generated voltage signal. The Aux A/D input is the top SMC
connector on the PCI4 Controller Card's mini-panel. See Figure D-1 for the identity of all the SMC connectors
on this mini-panel.
Uses of this input include the measurement of temperature, strain, or other non-electrochemical parameters.
This input is fully differential, with about 80 dB of common mode rejection. Be careful though, the allowed
common mode voltage range is only ± 11 volts with respect to the floating ground. Voltages outside this range
should not damage the instrument but they cannot be measured.
The scaling on this signal is ± 3 volts full scale, resulting in ± 30,000 counts on the A/D converter.
The signal conditioning circuitry on this input includes jumpers to select both input impedance and bandwidth.
See Appendix E for a description of these jumpers.
Appendix D -- I/O Connections for the PCI4 -- Aux A/D Input
Cell Connector
Use
Normally connected to the working electrode. This is the
high impedance negative input of the differential
electrometer. A 260 Ω series resistor at the cell end of the
coax cable on this input is required for system stability.
A driven shield for the working sense input. Normally
connected to the outer shield of a coax cable on pin 1.
Do not ground this pin!
The input to the PCI4 current measurement circuit. The
voltage on this point can be ±1.5 volt with respect to
floating ground.
A driven shield for the working electrode input. Normally
connected to the outer shield of a coax cable on pin 3.
Do not ground this pin!
The PCI4's floating ground. Should also be used to provide
a shield for the counter electrode if one is used.
Normally connected to the reference electrode. High
impedance positive input of the differential electrometer.
A 260 Ω series resistor at the cell end of the coax cable on
this input is required for system stability.
A driven shield for the reference electrode input.
Normally connected to the outer shield of a coax cable on
pin 6. Do not ground this pin!
Input to a voltage follower. Normally connected to the
cell's counter electrode. Used in ZRA mode to develop a
feedback signal.
The output of the PCI4 control amplifier. Normally
connected to the counter electrode of the electrochemical
cell being tested.
Table D-1
6-11
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