720A Operation and Maintenance Manual – Rev S – January 25, 2019
Page 17
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D-6 Detailed Use Description
This section provides a detailed description of how to use the 720A Digital Micro-
Ohmmeter to take resistance measurements.
Firstly, ensure that the unit is appropriately plugged into a power outlet. If using the 720-
BAT battery powered version of the meter, it is ideal that the unit’s batteries will be
charged before attempting to use the product. If your unit’s batteries are dead you can
operate the meter while charging the batteries at the same time but should allow an
additional ten (10) minutes in addition to the standard fifteen (15) minute warm up time
before attempting to take measurements.
The meter may be set up to operate as soon as the power is turned on, which can be
accomplished by flipping the “ON/OFF” switch upward on the unit’s front panel. The
unit’s display should engage immediately. One should allow the unit at least fifteen (15)
minutes of time to warm up before attempting to make measurements. If operating a
720A meter in a more extreme climate, a warm up period of thirty (30) minutes is ideal.
This warm up period allows the unit to adjust to the room’s ambient temperature and
enables it to accurately take/display measurements. During this warm up period, one
may also choose to perform a zero check for test lead/probe integrity if desired. Unless
performing test lead/probe integrity checks, the unit should otherwise be left alone while
turned on during this warm up period.
(Optional) Procedure to perform a zero check on a test lead/probe set:
i. Connect a set of leads/probes to the front panel via the VHI and
VLO banana jack terminals on the unit’s front panel.
ii. Short the leads/probes by touching the ends (i.e. alligator clips,
spear tips, etc.) of each cable to each other.
iii. Select
the 200 Ω range on the unit’s front panel.
iv. Reading should be within 5 display counts of zero.
Figure 8
720A Usage Example Diagram
