Commissioning
EF200F-C
112
Energy flow
Medium Fluid
Standards
Explanation
Heat/energy option
Steam
1)
‒
IAPWS-
IF97/ASME
For fixed process
pressure or if the
pressure is read in via
current input/HART
Heat
Gross calorific value
2)
in relation to mass
Net calorific value
3)
in relation to mass
Gross calorific value
2)
in relation to corrected
volume
Net calorific value
3)
in relation to corrected
volume
Gas
Air
NEL40
For fixed process
pressure.
Liquids
Water
IAPWS-
IF97/ASME
‒
1)
The measuring device is capable of calculating the volume flow, and other measured variables derived from
the volume flow, across all steam types with full compensation using the pressure and temperature. To
configure device behavior → See 10.5.2
2)
Gross calorific value: combustion condensation energy of the flue gas (gross calorific value > net
calorific value)
3)
Net calorific value: only combustion energy
Mass flow and energy flow calculation
The process pressure (p) in the process pipe is required to calculate the process
variables and the limit values of the measuring range.
With the HART device, the process pressure can be entered via the 4 to 20mA current
input or via HART from an external pressure measuring device (e. g. Cerabar M) or
entered as a fixed value in the External compensation submenu (→ See 10.5.2).
Steam is calculated based on the following factors:
• Fully compensated calculation of density using the "pressure" and "temperature"
measured variables
• Calculation based on overheated steam until saturation point is reached
Configuration of diagnostic behavior of the S871 Near steam saturation limit
diagnostic message Assign behavior of diagnostic no. 871 parameter set to Off option
(factory setting) as standard → See 12.3.1
Optional configuration of diagnostic behavior to the Alarm option or Warning option
→ See 12.3.1 option.
At 2 K above saturation, activation of the
S871 Near steam saturation limit
diagnostic message.
• The smaller of the following two pressure values is always used to calculate the density:
• Pressure measured directly at meter body or pressure read in via current input/HART
• Saturated steam pressure, which is derived from the saturated steam line (IAPWS-
IF97/ASME)
• Depending on setting in the Steam calculation mode parameter (→ See 10.4.3)
• If Saturated steam (T-compensated) option is selected, the measuring device only
calculates on the saturated steam curve using temperature compensation.
• If Automatic (p-/T-compensated) option is selected, the device calculates using full
compensation either along the saturation line or in the superheated region, depending
on the steam state.
• If Automatic (p-/T-compensated) option is selected in combination with one of the
application packages wet steam detection or wet steam measurement, the
measuring device can also calculate in the wet steam region.
For detailed information on how to perform external compensation, see → See 10.5.2.
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