5-1
SECTION 5: RETURN-GROUND-GUARD CONNECTIONS
The unit contains a currentmeter feature useful in measurement of different current sources.
1. Return Mode (RTN) (Grounded Return Mode)
This is the standard measurement configuration. The Ground jumper is installed between the Ground
(GND) post and the Return (RTN) post. The low potential side of the test specimen is connected to
Return. It can initially be isolated from ground or tied to ground. When it is connected to Return in this
mode, it will be grounded through the Ground jumper if it was initially isolated from ground. This mode
measures all output current from the test set.
If the low potential side of the test specimen will not or can not be isolated from ground, Return mode is the
hookup mode that must be used. Any connections made to Guard must be isolated from ground in this
mode and will bypass the currentmeter. All currents to Ground and Return will be measured in this mode.
2. Guard Mode
In this mode, the Ground jumper is connected to the Guard post and Ground post. The low potential side
of the test specimen must be isolated from ground and connected to the Return post. Only current to the
Return post will be measured by the currentmeter. Any stray leakage currents to ground or from sources
connected to Guard will bypass the currentmeter and not be measured such as stray leakage currents to
ground, stray currents to shields or
housings tied to Ground or Guard, etc. In this mode, the low potential side of the specimen must be
isolated from ground. If the low potential side of the specimen can not or will not be isolated from ground,
this mode can not be used to accurately measure current flow.
NOTE: Do not operate unit with the ground jumper removed or not connected to either Return or Guard.
Make sure the Ground post is connected to a good earth ground. See connection diagrams (Figure 5-1)
on next page.
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