Open Sense Lead Protection - Agilent Technologies 66111A User Manual

3 - Installation

Open Sense Lead Protection

The main output (output 1) of the dc source has built-in open sense protection circuitry that detects if
there is an open in either the positive or the negative remote sense lead or load lead path. For battery
powered devices, undetected open sense connections can cause incorrect battery charger calibration,
incorrect test results due to erroneous voltage settings, and low voltage phone shutdown due to a large
transient voltage drop.
To enable open sense lead detection from the front panel, press the
É
SENS:PROT, press to select ON, then press
enabled, save this state in location 0 and set the power-on state to RCL 0.
When this circuit is enabled, the sense and load leads are checked every time the output transitions from
disabled to enabled (off to on). If a lead opens while the output is enabled, this will not be detected
immediately by the open sense circuit. However, the output voltage will increase or decrease, depending
on which one of the leads is open. Figure 3-5 illustrates the actual output voltage change that occurs with
no load lead drop if a lead opens. Turning the output off, then on again, will cause the unit to check the
output sense and load leads and determine if a sense lead is open.
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0
Figure 3-5. Output Voltage vs. Programmed Voltage with Open Sense Condition
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Values will increase by about
+0.3 V under load conditions
Values will decrease by about
-0.1 V under load conditions
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Output key
Enter . To have the unit turn on with open sense detection
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PROGRAMMED VOLTAGE
p
, use to scroll to
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