Scanning Programme On Computer - Chauvin Arnoux C.A 25 Mode D'emploi

or in % Duty % =
Here we have :
3
3 + 2
Duty % =
To make this measurement with the C.A 25 or C.A 27 tachymeters, you must :
1) Check the amplitude of the signal input at the instrument. This makes it possible
to determine the threshold to be set.
Here the amplitude is greater than +1.1 V, so pins 1 and 3 of the FRB socket must
not be connected together.
2) Switch on the tachometer and set the rotary switch to "%".
3) The display directly gives the above result.
It may sometimes be necessary to make a prior frequency measurement. This
measurement allows the determination of the threshold to be selected. This may
be between +1.1 V at 1 kHz and +2.2 V at 10 kHz.
SCANNING PROGRAM ON THE COMPUTER (C.A 27 only)
We have seen that it is possible to remote read the C.A 27 via its RS 232 serial
interface. The program below, written in TURBO BASIC, gives an example of a
measurement reading.
Sending the 07 character wakes up the instrument. Next, sending 63 gives by
return the value of the measurement which is going to be read using the two stacked
WHILE...WEND loops.
The measurement reading is repeated as long as no key on the keyboard is
pressed.
t
1
x 100
t + t
1 2
x100 = 60 %
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