Martel Electronics 235 - Manual (Page 58)

The next display will be:
If enable is selected, the next display will prompt to select Volts or
Ohms as the input. Once this selection is made, the calibrator will set
the end point and the start point. The next display will be:
Press the INC key to initiate the ramp from the starting value. Press the
DEC key to initiate the ramp from the ending value. If the trip detect is
enabled, you must press the INC or DEC key twice. See the trip detect
description for more information. While the ramp is slewing, the
display will show:
The instantaneous value will be updating in the display. You will notice
periodic pauses in the display as the calibrator does internal calibration
cycles. This does not affect the output ramp and only causes a pause in
the displayed value.
The ramp function is accomplished by updating the output digital to
analog convertor (DAC) every 250 milliseconds with a new value. The
amount of output change for each update is a function of the total
ramp span and the length of time for the ramp to complete. The ramp
is capable of 1 LSD resolution per update. The actual resolution, or
amount of change per step, is dependent on the ramp amplitude and
time. The following formula can be used to calculate the ramp
resolution:
step size = (ending value – starting value)
(ramp time x 4)
Output Functions
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Sel Input Func
Ohms Volts
Slewing
xxxxxx
Volts RampRdy
0.00 xxxxxx