Advanced Measurement Technology 273A, User Manual

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Warning: Although the external cell is disconnected when the electrometer switch is set to
DUMMY, the potential on the Counter-Electrode lead can be as high as 100 V and
must be considered dangerous in case the switch is accidentally set to EXT.
4. INITIAL CHECKS
4.1. Introduction
The following procedure is provided to facilitate initial performance checking of the Model 273A.
Perform this procedure after you have inspected the instrument for obvious shipping damage.
Any damage noted should be reported to the carrier and to Princeton Applied Research. Be sure
to save the shipping container for inspection by the carrier.
If you have not used a Model 273A or 273 before, this procedure also will help acquaint you with
the operation of the instrument.
The Model 273A is checked using a resistor as the cell. These checks are adequate for
determining that the instrument is functioning normally.
Note that these procedures are not intended to demonstrate that the instrument meets
specifications, but rather to demonstrate that it has arrived in good working order. Each Model
273A receives a careful checkout before leaving the factory, and ordinarily, if no shipping
damage has occurred, it will perform within the limits of the specifications. If any problems are
encountered in carrying out these checks, contact the factory or the factory authorized
representative in your area for aid.
4.2. Required Equipment
Other than the Model 273A to be checked and its electrometer, no other equipment is required.
4.3. Setup
1. Set the Model 273A with electrometer on a lab bench. Or, if you prefer, mount it in a
standard 19-in. (47.5 cm) rack assembly. Instructions for rack mounting are provided in
Appendix B.
2. Set the Model 273A's POWER ON/OFF switch to the OFF position.
3. Set the Model 273A CELL ENABLE pushbutton switch to OFF.
4. Conned the Electrometer/Cell cable to the CELL INTERFACE connector at the rear of the
Model 273A. Bring the electrometer around to the side of the Model 273A for easy access.
5. Locate the shorting plug supplied with the electrometer. Plug it into the SENSE (gray) and
WORKING (green) electrometer jacks, shorting them together.
6. Set the switch located on the Electrometer to the DUMMY position. (In this position an
internal resistor acts as the cell.) Note: This is a locking switch. To change its setting the
toggle must be pulled out a millimeter or two as required to disengage the locking
mechanism.
7. Note the GROUND, COUNTER ELECTRODE, and WORKING ELECTRODE leads that
emerge from the electrometer. In the following checks, take care that the alligator clips at the
end of the leads don't short to each other or to any electrically conducting material.
8.