Varian TV 801 Mode D'emploi page 62

SPEED SETTING: PWM input signal to set the
pump speed. The PWM signal characteristics must
be the following:
•
frequency: 100 Hz +/-20%
•
ampitude: 24 V max
•
duty cycle range: from 25% to 75%
•
corresponding to an output frequency from
272 Hz to 646 Hz linearly.
NOTE
The duty cycle percentage is referred to the low
level portion of the PWM signal
PROGRAMMABLE ANALOG SIGNAL: this out-
put signal is a voltage (from 0 to 10 Vdc) propor-
tional to a reference quantity (frequency or power)
set by the user. The default setting is the fre-
quency (see the following example diagram).
FAULT: this open collector output signal is ON
when a system fault condition is detected.
PROGRAMMABLE SET POINT: this open collec-
tor output signal is enabled when the reference
quantity chosen (frequency, current or time) is
higher than the set threshold. The signal can be
"high level active" (that is the output is normally at 0
Vdc and becomes 24 Vdc when activated), or "low
level active" (that is the output is normally at 24 Vdc
and becomes 0 Vdc when activated). Moreover, if
the reference quantity is the frequency or the cur-
rent drawn, it is possible to set the hysteresis (in %
of the threshold value) to avoid bouncing.
For example:
- reference quantity: frequency
- threshold: 500 Hz
- hysteresis: 1%
- activation type: "high level"
The set point output stays at 0 Vdc until the fre-
quency becomes higher than 505 Hz (that is 500
Hz + 1% of 500 Hz), then the output goes at 24
Vdc and stays at 24 Vdc until the frequency be-
comes lower than 495 Hz (that is 500 Hz – 1% of
500 Hz).
It is possible to delay the set point checking for a
programmable delay time.
The PROGRAMMABLE SET POINT signal has
the following default settings:
- reference quantity: frequency
- threshold: 582 Hz
- hysteresis: 2%
- activation type: high level
- delay time: 0 second
The Navigator Software (optional) allows the op-
erator to set all the programmable feature.
When no external input-output device is available
this connector must be closed with the supplied
mating connector that short-circuits the START
and INTERLOCK inputs with the GROUND and 24
Vdc OUT (see the following figure).
57
TECHNICAL INFORMATION
NOTE
87-900-980-01(B)