WPI EVOM Manual - Notes and Warnings; Tips and Advice

EVOM™ Manual
World Precision Instruments 5
Notes and Warnings
Choice of current/range: The EVOM™ Manual has three ranges of current from 2
µA to 10µA and each current range has its own resistive upper limit up to 100K Ω:
• 10K Ω range = 10 µA
• 50K Ω range = 4 µA
• 100K Ω range = 2 µA
The auto range will adjust the current as needed from 2 µA to 10 µA depending on
the resistance.
General rules
• The higher the current the greater the stability of the measurement. The xed
ranges may be more consistent with a xed current for some cell lines.
• If a cell line is not expected to read above 10K Ω, then choose that xed range.
Use of the charger: The EVOM™ Manual's Li-ion battery will last 8 hours on its
own. The charging time is 5.5 hours with the unit powered o. The EVOM™ Manual
charger should not be plugged in all the time. The chager may be used to power the
EVOM™ Manual for normal and long-term use.
NOTE: In the higher resistance ranges (50K -100K ) there may be a slight instability
added from the noise of the power supply, in that case unplug it during those
measurements.
USB Drives: WPI has supplied a tested USB thumb drive. Most drives of 32 Gb
(USB2.0) or smaller sizes have been tested.
CAUTION: Not all USB drives work on the EVOM™ Manual.
To test a USB drive, see "Sample Resistance File (*.CSV)" on page 15. This test saves
a le to the drive and reads it back. A system message will report if the USB thumb
drive is usable, or it will display an error. If the USB thumb drive is not plugged in or it
is not recognized, a warning message will appear. Press Cancel and try again. The Store
function cannot be used on an unrecognized drive. EVOM™ Manual should respond
with “File saved” within 15 seconds. If “Saving le...” is still seen after 20 seconds, press
the Return key and use another USB thumb drive. Once a le has been saved, open
the le on a computer to verify the contents.
Tips and Advice
Out of Range Error
If you see –––– (5 dashes) on the main resistance display, then the resistance reading
is out of range. Check the ohms range setting to see if it can be increased to display a
higher resistance or set it to Auto . If the display still shows ––––, then go to the Blank
Handling screen and check the settings and the reading. A saved reading will show a
space (“ “) in the grid if the display shows out of range. Do not forget to reset the blank
to zero or go back to a control well resistance when you are nished.
NOTE: The 100K Range can read 5% over to 105K Ω.