42 cHAPTER 5: Advanced Operation
Model 425 Gaussmeter
5.4.1 Probe Serial
Number
You can view the serial number of the attached probe from the display of the
Model 425. This feature can be used to check the programming of extension cables.
To view the serial number, press Probe Setup. The probe serial number screen will
appear for approximately 3 s. The serial number is up to 10 digits in length.
Menu navigation:
Probe SetupQ (probe serial number screen appears for 3 s)
Interface command: PRBSNUM?
5.4.2 Field
Compensation
To improve accuracy, all Lake Shore probes have a magnetic field compensation table
stored in their EEPROM. Turning field compensation off causes the Model 425 to
ignore this table and calculate the field based on a nominal probe sensitivity.
Unless there is a specific reason, Lake Shore strongly advises users not to turn field com-
pensation off; it may reduce reading accuracy substantially.
Menu navigation:
Probe Setup (probe serial number appears for 3 s)Q (off, on)
Default: on
Interface command: PRBFCOMP
5.4.3 Extension Cable
Hall effect measurements make it necessary to match extension cables to probes
when longer cables are needed. When using an extension cable, the calibration in the
probe needs to be copied to the extension cable. Stored information can be viewed on
the front panel and read over computer interface to ensure proper mating.
In most cases, you can use uncalibrated extension cables; the probe calibration can be
transferred to the extension cable using the Model 425.
Follow this procedure to match a probe with an extension cable.
1. Attach the probe and power on the Model 425.
2. Press and hold Probe Setup for approximately 3 s.
3. Select HMPEC program and press Enter.
4. With the instrument on, remove the probe, and attach the HMPEC (extension)
cable to the Model 425. Press Enter.
D If a valid HMPEC cable is attached, a confirmation message stating
“Copying to Cable” will appear while the extension cable is pro-
grammed with the probe characteristics. When the copying process is
completed, the instrument returns to the normal display.
D If an invalid HMPEC cable is attached, and the probe matching process
is attempted, a message stating “invalid HMPEC cable” appears for 3 s.
If this occurs, verify that the HMPEC cable is properly connected. This
message will also appear if an attempt is made to copy to a previously
calibrated Lake Shore cable.
Menu navigation:
Probe Setup (press and hold for 3 s)Q HMPEC
5.4.4 Clear Zero Probe
Calibration
In some instances it may be useful to clear the results of the zero probe function. This
could be of value if the probe was zeroed improperly or if there is reason to believe the
probe is damaged. By clearing the results of the zero probe function, the instrument
clears all probe offset values.
Menu navigation:
Zero Probe (press and hold for 3 s)Q (yes, no)
Interface command: ZCLEAR
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