7
UK
4.3 Diagnostic function
Output 2 is used as diagnostic output based on the DESINA specification if
[OU2] = [dESI]�
• If there is no fault, the output is switched and carries UB+ (if P-n = PnP)
or UB- (if P-n = nPn)�
• In case of malfunctions in the following areas, the output is inactive:
-short circuit in output 1�
-EPROM function�
-RAM function�
-parameter setting�
-processor function�
4.4 Differential pressure measurement
Besides the main pressure connection
(1) the unit provides a ventilation
connection (2)� If both connections are
connected to the pressure system, the
unit can work as a differential pressure
sensor�
For proper function the following conditions must be met:
• The pressure at the main connection must always be greater than the
pressure at the ventilation connection�
• However, the pressure at the ventilation connection must not exceed
10 bar�
Note:
For differential pressure measurement the measurement accuracy deviates from
the specified accuracy (→ 12 Technical data). The deviation depends on the
amount of system pressure� It is 3�5 to 8�3 mbar per 1 bar system pressure�
The deviation can be minimised by setting an offset value (→ 9.3.5 Zero point
calibration)�
