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different. The more-rectangular end plugs into the computer and the more-square end plugs into the Reference
3000.
A suitable USB cable was included with your Reference 3000 shipment. If this cable is lost, you can replace it
with a cable from your local computer retailer.
The Reference 3000 is a High Speed USB 2.0 peripheral, capable of data transfer at 480 Mbits/second. If it is
plugged into a computer port incapable of High Speed operation it will downgrade to USB 1.1 full speed
operation (12 Mbits/second).
The Reference 3000 USB port is compatible with Revision 1.1 and 2.0 of the USB specification. It supports the
Windows Plug-n-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 an input jack for a K Type thermocouple. The ISO standard calls for color-coded
mini-thermocouple connections. Yellow is the color assigned to K Type 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 K type thermocouple.
The Reference 3000 uses a temperature measurement IC to convert the thermocouple output to a useable
voltage. It 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 volts 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.
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 an non-insulated thermocouple immersed in your electrochemical cell
can also cause erroneous readings.
Misc I/O Connector
The Misc (Miscellaneous) I/O connector is a multipurpose connector. It contains both digital and analog signals
used to interface 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.
Chapter 6 -- Panel Indicators and Connectors--Rear Panel
Obviously data transfer speed will be slower if this occurs.
CAUTION
6 - 5
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