Endress+Hauser Proline Promass 83 - Page 63

Device Functions Proline Promass 83 MODBUS RS485 7 Block OUTPUTS
Endress+Hauser 63
MEASURING
MODE
(continued)
4004 Description of the individual options:
STANDARD
The current output signal is proportional to the measured variable.
The flow components outside the scaled measuring range (defined by the 0_4 mA
VALUE m and the 20 mA VALUE n) are taken into account as follows for signal
output.
• If one of the values is defined as equal to the zero flow (e.g. VALUE 0_4 mA =
0 m
3
/h), no message is given if this value is exceeded or not achieved and the
current output retains its value (in example 4 mA). If the other value is
exceeded or not achieved, the message “CURRENT OUTPUT AT FULL SCALE
VALUE” appears and the current output responds in accordance with the
parameter setting in the function FAILSAFE MODE (4006).
• If both values defined are not equal to the zero flow (for example VALUE 0_4
mA = –5 m
3
/h, VALUE 20 mA = 10m
3
/h), the message “CURRENT OUTPUT
AT FULL SCALE VALUE” appears if the measuring range is exceeded or not
achieved and the current output responds in accordance with the parameter
settings in the function FAILSAFE MODE (4006).
A0001248
Fig. 15 : Example for STANDARD measuring mode
SYMMETRY
The current output signal is independent of the direction of flow (absolute amount
of the measured variable). The 0_4 mA VALUE m and the 20 mA VALUE n must
have the same sign (+ or -). The “20 mA value” o (e.g. backflow) corresponds to
the mirrored 20 mA value n (e.g. flow).
A0001249
Fig. 16 : Example for SYMMETRY measuring mode
! Note!
• The direction of flow can be output via the configurable relay or status outputs.
• SYMMETRY cannot be selected unless the values in the VALUE 0_4 mA
(4002) and VALUE 20 mA (4003) functions have the same sign or one of the
values is zero. If the values have different signs, SYMMETRY cannot be
selected and an “ASSIGNMENT NOT POSSIBLE” message is displayed.
PULSATING FLOW
If flow is characterized by severe fluctuations as is the case, for example, with
reciprocating pumps, flow components outside the measuring range are buffered,
balanced and output after a maximum delay of 60 seconds. If the buffered data
cannot be processed within approx. 60 seconds, a fault/notice message appears.
Under certain plant conditions, flow values can aggregate in the buffer, for
example in the case of prolonged and unwanted fluid backflow. However, this
buffer is reset in all relevant programming adjustments which affect the current
output.
Function description
OUTPUTS → CURRENT OUTPUT 1 → CONFIGURATION
Q
20
4
0
mA
➀➁
Q
20
0
mA
4
➂➀➁