20
Measuring Mode
Version: FAU_M_EN_170308_E004
4.1.7.
Actual Flow with uUnit and Analogue Output in Percent
1
st
line:
scaled flow rate with unit
2
nd
line:
analogue output in percent
Operating Priciple of the Control Inputs and the Outputs
4.2.
The FAU has two frequency inputs and two control inputs which can influence different outputs and the internal
counters. The control outputs are low-active, they have to be connected with the potential reference of the
pickup supply. All outputs except for the analogue output are open-collector outputs.
4.2.1.
RESET Control Input (terminals 11/7)
Activating this input will reset the internal pulse counter and totaliser to zero. Furthermore there is no
incrementation or decrementation of the counters.
This function is also available via in the displays under chapter 4.1.3 and 4.1.4.
Examples: changing of the measuring medium or a change of shifts.
4.2.2.
HOLD Control Input (terminals 12/7)
The following happens while this input is active:
•
The FAU maintains the present analogue level which is available at the analogue output.
•
Reverse flow detection is disabled. The output holds the last-detected direction.
•
Totaliser and pulse counter remain on their present count.
•
Limit MIN and MAX are inactive
"HOLD active" in the 2nd line of the display indicates the HOLD input is active. The display of the actual flow is
not affected by the HOLD input.
The HOLD function is useful when you do not want to evaluate the flow rate of start portions or while the flow
meters are purged.
4.2.3.
Divider Output (terminals 13/14)
This output supplies external counters with a divided frequency (see chapter 3.3). The output sends an output
pulse after the pre-selected volume has passed through the flow meter (see chapter 3.3.2). The pulse time (see
chapter 3.3.3) is adjustable). After that the transistor is blocking again.
4.2.4.
MAX Limit (terminals 15/16)
The open-collector track of this output conducts, when the actual flow exceeds the MAX limit (see chapter
3.4.1).The output is blocked ("OC-track blocked"), when the actual flow bypasses the value for MIN limit less
hysteresis (see chapter 3.4.2).
