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Chapter 3 Front-Panel Operation
Remote Voltage Sensing
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Remote Voltage Sensing
Remote voltage sensing is used to maintain regulation at the load and reduce
the degradation of regulation that would occur due to the voltage drop in the
leads between the power supply and the load.
By connecting the power supply for remote voltage sensing, voltage is sensed
at the load rather than at the power supply’s output terminals. This will allow
the power supply to automatically compensate for the voltage drop in
applications with long lead lengths as well as to accurately read back the
voltage directly across the load.
When the power supply is connected for remote sensing, the OVP circuit senses
the voltage at the sensing points (load) and not the output terminals.
CV Regulation
The voltage load regulation specification in chapter 8 applies at the output
terminals of the power supply. When remote sensing, add 5 mV to this
specification for each 1 V drop between the positive sensing point and (+)
output terminal due to the change in load current. Because the sense leads are
part of the power supply’s feedback path, keep the resistance of the sense leads
at or below 0.5
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per lead to maintain the above specified performance.
Output Rating
The rated output voltage and current specifications in chapter 8 apply at the
output terminals of the power supply. With remote sensing, any voltage
dropped in the load leads must be added to the load voltage to calculate
maximum output voltage. The performance specifications are not guaranteed
when the maximum output voltage is exceeded. If the excessive demand on
the power supply forces the power supply to lose regulation, the
Unreg
annunciator will turn on to indicate that the output is unregulated.
Output Noise
Any noise picked up on the sense leads also appears at the output of the power
supply and may adversely affect the voltage load regulation. Twist the sense
leads to minimize external noise pickup and run them parallel and close to the
load leads. In noisy environments it may be necessary to shield the sense leads.
Ground the shield at the power supply end only. Do not use the shield as one
of the sense conductors.