Operating instructions

Description
3.3 Operation with natural gas
SIPART PS2 with and without HART communications
Operating Instructions, 09/2008, A5E00074631-08
21
See also
Certificates (http://www.siemens.com/processinstrumentation/certificates)
3.3.2 Natural gas as an actuator medium
Introduction
Normally, you operate the positioner with compressed air. Natural gas has been approved as
an actuator medium for intrinsically safe positioners with the "EEx ia" type of protection.
Note
Quality of natural gas
Only use natural gas which is clean, dry and free from additives.
Functional principle
The positioner releases the used natural gas through the exhaust air outlet E. The exhaust
air outlet E is equipped with an attenuator.
As an alternative to this standard configuration, the exhaust air outlet can be replaced with a
G¼ screwed fitting. You have to dismantle the attenuator for this purpose.
Maximum values for escaping natural gas
Natural gas escapes parallel to the exhaust air outlet E:
● From the enclosure vent at the bottom side of the device
● From the control air outlet near the pneumatic connections
This escaping natural gas cannot be collected and carried off. Please refer to the following
table for the maximum bleeding values.
6DR5x1x-xExxx 6DR5x2x-xExxx
Single-acting Double-acting
Bleeding process Operating
mode
[Nl/min] [Nl/min]
Operation,
typical
0.14 0.14
Operation,
max.
0.60 0.60
Bleed the enclosure volume through the bottom
side of the device. Purge air switch is at "IN":
Error case,
max.
60.0 60,0
Operation,
typical
1.0 2.0 Bleed through the control air outlet near the
pneumatic connections:
Operation,
max.
8.9 9.9