INFICON BPG402-SP ATM to Ultra-High Vacuum Gauge (Profibus) - Manual (Page 30)

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tira47e1 (2005-08) BPG402SPv1.cp
Instance 3 and 4 of the Analog Sensor Input Function Block describe the
functionality of the threshold potentiometers used to set the gauges switching
functions ("Setpoint A and B,
→ [3]).
Instance Switching Function
("Setpoint")
3 A
4 B
ID Name Structure Data type Bytes Access Store
19 Process Value
(PV) Simple According to
Parameter Data
Type - 1/2_R V
20 Status Simple UINT8 1 1/2_R V
21 Data Type Simple UINT8 1 2_R/W N
22 Data Units Simple UINT16 2 2_R/W N
23 Reading Valid Simple Boolean 1 1/2_R V
The Process Value contains the current setting of the threshold potentiometers for
"Setpoint A" and "Setpoint B" in the currently selected data unit (ID 22) and data
type (ID 21).
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 (
→ [3]).
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
The threshold voltages of the Setpoint potentiometer can be converted into a
pressure value by means of the following formulas:
p
mbar
= 10
(U - 7.75) / 0.75
Where: U is the threshold voltage (0 … +10 V) of the corresponding Setpoint (A,
B), measured at the D-Sub connector (sensor cable connector) of the
gauge (
→ [3]).
This parameter is remains on "0".
Two data types are supported: Float and Integer16.
In cyclic data traffic, the data type cannot be modified. After the gauge is switched
on, the value stored in the EEPROM is loaded. The data type setting can only be
modified when the gauge is in the IDLE status. By defining the configuration data
for cyclic data traffic (selection of standard telegram), the data type used in the
selected standard telegram is taken over. All settings previously made in acyclic
data traffic are thus overwritten.
If the data type is set in one instance, that data type setting applies to all instances.
Likewise, when a standard telegram is selected, the data type used by that
standard telegram will be valid for all instances.
Coding Data type
3 Integer16
8 Float (default)
3.2.4 Analog Sensor Input
Function Block
SLOT 1 / Instance 3, 4
3.2.4.1 Process Value ID 19
3.2.4.2 Status ID 20
3.2.4.3 Data Type ID 21