Instrument Components - Siemens PROFIBUS PA SIPART PS2 Manual

Design and Functional Principle
2.2

Instrument Components

1 Input: Supply air
2 Output: Actuating pressure Y1
3 Display
4 Output: Actuating pressure Y2
5 Operating keys
6 Restrictor
6.1 Restrictor Y1
*)
6.2 Restrictor Y2
*)
in double-acting actuators
Figure 2-1 View of the positioner (cover open); plastic housing
24
The limit value alarms are output by the alarm option module which can
monitor and report the function of the positioner and the actuator addi-
tionally through a fault message output. The value of the control differ-
ence dependent on the travel time is monitored in automatic mode. The
fault signal is always set when the control error cannot be leveled after
a certain time because for example the valve is blocked or the mains
pressure is insufficient. The three digital outputs are implemented as
semiconductor outputs and are error self-reporting, i.e. the outputs re-
spond even when the power supply fails or the electronics are defec-
tive.
The actuator can also be blocked or driven to its final positions depend-
ing on the configuration for example by an external event via a digital
input (DI2) on the alarm module.
If you require electrically independent limit value messages from the
standard controller, you will have to use the SIA module with the slot
initiators instead of the alarm module.
7 Transmission ratio selector
8 Silencer
9 Adjustment wheel for friction clutch
*)
10 Terminals options modules
12 Ground cable (only for plastic housing)
13 Bus cable
14 Terminal plate on cover
15 Purging air switch
SIPART PS2 PA Manual
A5E00127926-03