Siemens SITRANS P500 Notice De Service page 16

3.4.2 Connection of the negative pressure line to the closed vessel
When taking measurements in a closed container without or with little condensation formation, the negative pressure line is
not filled.
h Start of scale value
U
h Full scale value
O
p Pressure
Measurement assembly on a closed container:
no or little condensation separation
When taking measurements in a closed container with strong condensation formation, you must fill the negative pressure
line (mostly with the condensation of the measured medium) and install a condensation pot.
For measurement on open vessels there is no need to connect the minus pipework, since the minus side is open to the
atmosphere.
4 Connecting
4.1 Basic safety instructions
WARNING
Unsuitable cables and/or cable glands
Danger of explosion in hazardous areas.
● Only use suitable cables and cable glands complying with the requirements specified in Chapter "Technical data
(Page 27)".
● Tighten the cable glands in accordance with the torques specified in Chapter "Technical data (Page 27)".
● When replacing cable glands use only cable glands of the same type.
● After installation check that the cables are seated firmly.
14
Δp Start of scale value to be adjusted
MA
Δp Full scale value to be adjusted
ME
ρ Density of the measured medium in the container
g Acceleration due to gravity
Formula:
Start of scale value
Δp = ρ · g · h
MA U
Full scale value
Δp = ρ · g · h
ME O
SITRANS P500 with HART
A5E02344532-03, 04/2013