INFICON HPG400-SP ATM to Ultra-High Vacuum Gauge (Profibus) - Manual (Page 32)

32
tira36e1-a (0310) BPG/HPG400 v1.cp
Instances 3 and 4 of the Analog Sensor Input Function Block describe the func-
tionality of the two switching functions (Setpoint A / Setpoint B) of the gauge
(setting the switching functions
→ [2], [3] for BPG400-SP and [5], [6] for
HPG400-SP):
Instance Setpoint
3 A
4 B
With Process Values (ID 19), the current threshold setting (made by means of the
potentiometers) is read; with Status, the relay status (open/closed) can be read.
ID Name Structure Data type Bytes Access Store
19 Process Value
(PV) Simple Unsigned16 - 1_R
2_R D
20 Status Simple Unsigned8 1 1_R
2_R D
21 Data Type Simple Unsigned8 1 2_R
2_W N
22 Data Units Simple Unsigned16 2 2_R
2_W N
23 Reading Valid Simple Boolean 1 1_R
2_R D
The Process Value contains the current setting of the threshold potentiometers for
"Setpoint A" and "Setpoint B" in the currently selected data unit and data type.
If the pressure drops below the set threshold, the relay is closed. If after that, the
pressure rises above that threshold with a hysteresis of 10%, the relay is opened
again (
→ [2], [3] for BPG400-SP and [5], [6] for HPG400-SP).
The Process Value PV is output in the currently selected data unit and data type.
Values output in the pressure unit COUNTS can be converted into a pressure value
by means of the following formulas:
p
mbar
= 10 (COUNTS / 2000) - 12.5
p
mbar
= 10 (COUNTS - 22 999) / 2444
The threshold voltages of the Setpoint potentiometer converted into a pressure
value by means of the following formulas:
p
mbar
= 10 (1.23011 × U) - 9.30102999
p
mbar
= 10 (9 × U / 10) - 6
Where: U is the threshold voltage [V] of the corresponding Setpoint (A, B),
measured at the D-Sub connector (sensor cable connector) of the gauge
(
→ [2], [3] for BPG400-SP and [5], [6] for HPG400-SP).
The switching functions work only at pressures <100 mbar. If a higher
threshold has been selected, the relay is only activated at pressures
lower than 100 mbar.
3.2.4 Analog Sensor Input
Function Block
Instances 3
and 4 / SLOT 1
3.2.4.1 Process Value
BPG400-SP
HPG400-SP
BPG400-SP
HPG400-SP