INFICON BPG402-Sx ATM to Ultra-High Vacuum Gauge - Manual (Page 37)

tina46e1-a (2010-03) BPG402.om
37
The BPG402-S, SL have one, the gauges BPG402-SD and BPG402-SP have two
independent, manually adjustable switching functions. Each switching function has
a floating, normally open relay contact. The relay contacts are accessible at the
sensor cable connector (
→ 19, 20).
The threshold values of the switching functions can be set within the pressure
range 1×10
-9
mbar … 100 mbar via potentiometers "SETPOINT" (BPG402-S, SL)
or "SETPOINT A" and "SETPOINT B" (BPG402-SD, SP).
The following rule applies:
U
Threshold
= 0.75 × (log p
Setpoint
– c) + 7.75
Where constant c is pressure unit dependent ( → Appendix A).
Me
asu
red va
lue
Off On
Switching function
Measuring Signal
(Pressure p)
(Setpoint A, B)
Time t
Off
U
Threshold
Hysteresis
10% U
Threshold
The hysteresis of the switching functions is 10% of the threshold setting.
4.12 Switching Functions