TDI-Dynaload Division
WCL488 Series Water Cooled Electronic Loads
Operation & Programming Manual
402828, Rev. B1
Page 27
Current Limit Setting
The current limit function acts as a “brick wall”. The load will not permit the
current to
exceed
the numeric set point. When prompted, press ENTER to select this as a function. Then simply
enter the value using the numeric keypad and press ENTER. If the limit is achieved by the load,
an alarm will be indicated and the load will continue at the limit point. This is considered a
MINOR FAULT.
Range Switching and Current Limit Set Point
Unless set by the user, the default set point for current limit is 105% of the current range selected.
This default is affected by current range selection. A current limit cannot be set greater than
105% of range. If a unit is switched to a current range that is lower than the current limit set
point, the 105% maximum of the range selected will overwrite the limit. If the unit is then
returned to the higher current range, the current limit will remain at 105% of the previous range.
It will be necessary to reset the limit point if higher current is desired. If the current limit is set to
less than 105% of the lowest current range, the set point will not be affected by switching to a
higher current range.
Voltage Limit Setting
The voltage limit function acts as a protection to both the load and the source under test. If the
voltage limit point is achieved, the load will disconnect from the source. An alarm condition will
be indicated and will be a MAJOR FAULT. The load will not reconnect until the input voltage is
below the limit set point. When prompted, press ENTER to select the function, then enter the
numeric value using the keypad and press ENTER.
Power Limit Setting
The power limit function acts as a “brick wall”. The load will not permit the power level to
exceed the numeric set point. If the voltage continued to rise once in power limit the load will
respond by continually reducing the current to meet the prescribed set point. If the set point is
achieved an alarm will be indicated and will be a MINOR FAULT. When prompted, press
ENTER to select the function, enter the numeric value using the keypad and press ENTER.
Slew Rate Adjustment
The slew rate adjustment sets both the rise and fall in time microseconds for a full-scale transition
within the selected range. This is utilized to compensate for the inductance in long load input
cables that could cause oscillation and/or overshoot. The slew rate setting is set at the factory for
100us and can be programmed from 10us and 4,000us when Fast Slew is selected (default). When
Slow Slew is selected the slew rate can be set between 1,000us (1ms) and 400,000us (400ms).
See Slew Fast/Slew Slow. When prompted press ENTER. Then enter the desired slew value in
microseconds. Finish by pressing ENTER.
Encoder Resolution Setting
The rotary digital encoder used for manual adjust can be set to different resolution settings. This
will allow the user to set for a fine or coarse knob control. This function is active in all modes of
operation, but depending on the mode, a setting that seems good in the constant current mode
