Panel Indicators and Connectors – Rear Panel
61
The Reference 3000
USB
port is compatible with Revision 1.1 and 2.0 of the USB specification. It supports the
Windows Plug and Play mechanism, including dynamic connect/reconnect.
The front-panel
USB
LED should be green whenever a valid computer to Reference 3000 connection has been
made and both the computer and Reference 3000 are fully powered.
Thermocouple Input
The Reference 3000 has a
T/C Type K
jack for a type K thermocouple. The ISO standard calls for color-coded
mini-thermocouple connections. Yellow is the color assigned to type K thermocouples. The mating connector
on your thermocouple should therefore be yellow.
Possible uses for temperature measurement in an electrochemical test include:
Looking for a temperature rise at end-of-charge on a battery.
Measuring ambient temperature prior to a corrosion measurement.
Measuring temperature in a cell before making a CV measurement that will be used to calculate
reaction kinetics.
Gamry Instruments chose not to provide a thermocouple with the Reference 3000. There is simply too much
variety in the mechanical design of thermocouple probes. Commercial thermocouples designed for
measurement in air, on solid surfaces, and in immersion service are available from a variety of vendors. Make
sure you get a type K thermocouple.
The Reference 3000 uses a temperature-measurement IC to convert the thermocouple output to a usable
voltage t outputs a voltage that is nominally 10 mV per degree Celsius. The IC used, the Analog Device
AD594A, is rated for an accuracy of 3
C. Even this accuracy is only achieved when the Reference 3000 is
calibrated. The scaling at the A/D converter is
3 V full scale, or
300
C full scale.
The Reference 3000 calibration script has an optional section for thermocouple calibration. An ice-water bath
and a beaker of boiling water provide convenient standards for a two-point calibration.
Misc. I/O Connector
The
Misc.
(Miscellaneous)
I/O
connector is a multipurpose connector. It contains both digital and analog
signals used to connect external devices to the Reference 3000.
All of its signals are isolated from both earth ground and the Reference 3000’s Floating Ground. The device
connected to this connector establishes a ground reference. This isolation allows the
Misc. I/O
connector to be
connected to earth-grounded apparatus, without compromising the Reference 3000’s ground isolation.
A full description of this connector can be found in Appendix C of this manual. This appendix includes details
such as connector pin-out, output and input voltage-levels, and full signal descriptions.
The following list is a short description of the signals in the
Misc. I/O
Connector and their uses:
Sync Out and Sync In signal allow two or more Reference 3000s to use one data-acquisition clock.
Four digital outputs can be used to turn on external devices under control of an Explain experimental
control script.
Caution:
One side of the thermocouple is connected to the Reference 3000’s Floating
Ground. An improper connection to the thermocouple input can compromise the Reference 3000’s ability
to float, and invalidate data collected on earth-grounded cells. A connection to a non-insulated
thermocouple immersed in your electrochemical cell can also cause erroneous readings.
