Technical data Proline Promass E 100 Modbus RS485
84 Endress+Hauser
Calculation example for gas
• Sensor: Promass E, DN 50
• Gas: Air with a density of 60.3 kg/m³ (at 20 °C and 50 bar)
• Measuring range (liquid): 70 000 kg/h
• x = 125 kg/m³ (for Promass E, DN 50)
Maximum possible full scale value:
max(G)
=
max(F)
· ρ
G
: x = 70 000 kg/h · 60.3 kg/m³ : 125 kg/m³ = 33 800 kg/h
Recommended measuring range
"Flow limit" section → 93
Operable flow range Over 1000 : 1.
Flow rates above the preset full scale value do not override the electronics unit, with the
result that the totalizer values are registered correctly.
Input signal External measured values
To increase the accuracy of certain measured variables or to calculate the corrected volume
flow for gases, the automation system can continuously write different measured values to
the measuring device:
• Operating pressure to increase accuracy (Endress+Hauser recommends the use of a
pressure measuring device for absolute pressure, e.g. Cerabar M or Cerabar S)
• Medium temperature to increase accuracy (e.g. iTEMP)
• Reference density for calculating the corrected volume flow for gases
Various pressure transmitters and temperature measuring devices can be ordered
from Endress+Hauser: see "Accessories" section → 81
It is recommended to read in external measured values to calculate the following measured
variables:
• Mass flow
• Corrected volume flow
Digital communication
The measured values are written from the automation system to the measuring device via
Modbus RS485.
16.4 Output
Output signal Modbus RS485
Physical interface In accordance with EIA/TIA-485-A standard
Terminating resistor • For device version used in non-hazardous areas or Zone 2/Div. 2: integrated
and can be activated via DIP switches on the transmitter electronics module
• For device version used in intrinsically safe areas: integrated and can be
activated via DIP switches on the Safety Barrier Promass 100
Signal on alarm Depending on the interface, failure information is displayed as follows:
Modbus RS485
Failure mode Choose from:
• NaN value instead of current value
• Last valid value
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