Chapter 3 Front-Panel Operation
Remote Voltage Sensing at the Front and Rear Terminals
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Remote Voltage Sensing at the Front and Rear Terminals
Rem ote voltage sensing is used to maintain regulation at the load and reduce
the degradation of regulation that would occur due to the voltage drop i n the
leads between the power supply and the load.
By connecting the power supply for remote voltag e 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 lo ng 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 regul ation 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 posi tive sensi ng point and (+)
output terminal due to the change in load current. Because the sense le ads are
part of the power supply’s feedback path, keep the resistance of the sense leads
at or below 0.5
Ω
per lead to maintain the above specified performance.
Output Rating
The rated output vo ltage and current specificati ons in chapter 8 apply at the
output terminals of the power suppl y. With rem ote sensin g, any voltage
dropped in the load leads must be added to the load voltage to calculate
maximum output voltage. The performance specifications are not g ua ra nt eed
when the maximum outp ut 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 pic ked up on the sense leads also appears at the output of the power
supply an d may adver sel y affect the voltage lo ad 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
.
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