Elgas miniELCOR, Operation Manual, Page: 9 / 131

miniELCOR
2
For communication with its superior system, the device has a serial interface
RS-232 and RS-485. Various communication protocols installed in the device allow
easier connection to the SCADA systems. The device cooperates with common
phone, radio, GSM, and GPRS modems, and in case of an alarm condition, it can
initiate the connection.
The device can be enhanced by one non-metrology converter for measuring
pressure or temperature. This enhancement can be performed without breaking the
official mark on an already installed device.
1) Basic configuration of the device offers following inputs and outputs:
-
analog input (pressure P - metrologic channel)
-
analog input (temperature T - metrologic channel)
-
4x digital input DI1 to DI4 (binary, pulse); input DI1 can be used for connecting
encoder NAMUR
-
4x digial output DO1 to DO4 (binary, pulse, analog)
-
communication channel RS485/RS232 for communication with suprordinate
systém
-
input of external power supply
-
option: connection one digital pressure or temperature transmiter EDTxx (as
nometrologic) to internal bus by help expansion board KP 065 08. This
enhancement can be accomplished by end user on already installed device
without breaching of metrological seal.
2) Device variant with SCR encoder ensures following inputs and
outputs:
-
The same like at basic device variant ( see ad 1) however without possibility
of connection of digital transducer EDTxx
-
1x input for SCR encoder connection by means of extention board KP 065 09
The device can be configured using the supplied SW [22] for PCs. This SW also
allows the readout, display and archive of both the immediate measured values as
well as the contents of the internal device archives.
1.2 Function principle
1.2.1 Conversion using equation of state
The device obtains data on the gas flowing through via impulses (N) from an lf
or hf sensor located in the gas meter. The volume at the measuring conditions (V) is
calculated from the number of impulses (N) and gas meter constant (k
p
).
The device obtains other data on the gas flowing through from the temperature
and pressure converters – gas temperature (t) and absolute pressure at measuring
conditions (p). This data is used to calculate the conversion factor (C) which is
influenced also by these other factors: Absolute temperature at base conditions (T
b
),
absolute pressure at base conditions (p
b
) and compressible factor of the gas at base
conditions (Z
b
).