Omega Vehicle Security DP97 - Manual (Page 9)

Page 6
The calibration kit option (two precision resistors) is required to perform re-calibration.
No additional instruments are required since the DP97 self-calibrates as follows:
Caution: Do not proceed unless specified resistors are available. Failure to do so
may invalidate the warranty.
a) With the supply disconnected, remove the instrument
case cover by removing the two screws on the rear
panel and sliding the cover off the rear of the
instrument.
b) Insert the jumper JP1 (shorting connector) – this
places the DP97 into self-calibrating mode.
Connect the supply and switch on*. Calibration is
simply a matter of connecting the precision resistors in
sequence. The necessary value of the resistor, together
with the input to which it has to be applied is indicated
on the display. The steps are as follows:
*At this point, the existing calibration has now been over-written by default
values. The procedure should therefore now be completed.
i) Connect 100 Ohm calibration resistor to PRT INPUT a.
ii) Press “SPAN s s ” and display will show a value close to 100 Ohms. If the
value shown is wrong by more than 1.00 Ohms, a fault exists and the
Instrument must be returned for rectification.
iii) Press “SPAN s s ” again and the instrument will compute the average value
of 16 readings of the resistor value.
iv) When the display reads “A = 250”, connect the 250 Ohm calibration
resistor to input A.
v) Press “SPAN s s ” and display will show a value close to 250 Ohms. If the
value shown is wrong by more than 1.00 Ohms, a fault exists and the
instrument must be returned for rectification.
vi) Press “SPAN s s ” again and the instrument will compute the average value
of 16 readings of the resistor value.
vii)
Repeat steps (I) to (vi) for input B.
The DP97 then returns to a normal power-up state, PRT A, degrees C.