Section 2 - Operation; Front Panel Controls - Tektronix 067-0883-99 Instruction Manual

UNIVERSAL LOAD UNIT
SECTION 2
OPERATION
FRONT PANEL CONTROLS
CHANNEL SELECT Control. This 13 position rotary switch connects one
of the 13 channels to other Universal Load Unit front panel controls
including: CURRENT ADJUST, CURRENT LIMIT, CHOP/SWITCH, OVER VOLTAGE TEST,
to indicators including: Digital Multimeter and OUT-OF-REGULATION Lights
and to the External Input Amplifier. The CHANNEL SELECT control also
switches the AC output voltage available at the RIPPLE OUT
(+)
connector.
OVER VOLTAGE TEST Control. The OVER VOLTAGE TEST control is an end-
of-rotation switch that inserts (or excludes) an internal 75K resistive
divider in series with the remote sense line of the selected channel. CW
rotation increases the magnitude of 'the output voltage of the selected
supply under test. Note that this control will function only if the output
is remote sensed. Caution is indicated in that using this control in any
but the OFF (detented) position may cause damage to the supply under test.
Also, if the supply under test does not have an over-voltage limit, the
ULU's crowbar may be initiated causing an open fuse, damage to the supply
under test or both.
CURRENT ADJUST Control. The CURRENT ADJUST control is a combination
push-pull switch and dual potentimeter. Pulling out on this control engages
the current adjust function; pushing in disengages it. With the control
pulled out, CW rotation increases and CCW rotation decreases the programmed
current level (in positive channels 1 through
6)
to the full cell current.
Note that CURRENT ADJUST control rotations are reversed for negative
channels 7-12. In the individual chop mode, the transition level current
is set with the CURRENT ADJUST potentiometer (with the push-pull switch
in).
CURRENT LIMIT Control. The CURRENT LIMIT control is a momentary contact
push button switch. Pushing this switch causes the selected channel to
draw its maximum safe current. The CURRENT LIMIT switch overrides both
programmed current and the setting of the CURRENT ADJUST control. Current
magnitudes are a function of the channel number, its voltage and its
internal protection circuitry.
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