User Manual
E115-P
Page 28
FW_E115-P_M_v0301-01_EN
7
ANALOG OUTPUT
7.1 OUTPUT
If the analog output is not used, it can be disabled to minimize power
consumption and save battery life. When the output is disabled, a current of
about 2 mA is generated and the unit can still be supplied from this signal
(provided a power supply is connected).
While powering-up the loop, the initial current is approximately 2 mA.
When the output is enabled, it can take a few seconds before the correct
current is generated.
7.2 RATE SELECT
The analog output signal can be set to the following input value:
●
Signed
: a negative flowrate results in a minimum output value (in most
cases 4 mA).
●
Absolute
: a negative flowrate will result in a normal positive analog
output signal as if it is a positive flow.
●
Rate A
: according to the calculated flowrate for forward flow.
●
Rate B
: according to the calculated flowrate for reverse flow.
7.3 RATE MIN (4MA)
Enter the flowrate at which the output should generate the minimum signal
(4 mA) – in most applications at flowrate “0”.
The number of decimals displayed depends on the settings in
2.3: FLOWRATE A > DECIMALS
.
The measuring units and the time (L/min for example) depend on the
settings in
2.1: FLOWRATE A > UNIT
and
2.2: FLOWRATE A > TIME
and are displayed
during editing.
If required, you can program the analog output 'up-side-down'. The 4 mA
then represents the maximum flowrate.
For example, enter 800 L/min.
7.4 RATE MAX (20MA)
Enter the flowrate at which the output should generate the maximum signal
(20 mA) – in most applications at maximum flow.
The number of decimals displayed depends on the settings in
2.3: FLOWRATE A > DECIMALS
.
The measuring units and the time (L/min for example) depend on the
settings in
2.1: FLOWRATE A > UNIT
and
2.2: FLOWRATE A > TIME
and are displayed
during editing.
If required, you can program the analog output 'up-side-down'. The 20 mA
then represents the minimum flowrate.
For example, enter 0 L/min.
7.5 CUT-OFF
A low flow cut-off can be set as a percentage of the full range of 16 mA, for
example, to ignore leakage.
When the flow is less than the required rate, the current will be the
minimum signal (4 mA, or 20mA when the analog output is programmed
‘up-side-down’).
CUT-OFF CALCULATION EXAMPLES
Cut-off
Rate-min
4 mA
Rate-max
20 mA
Required rate
before reading
Output
at required rate
2.0%
0 L/min
100 L/min (100-0)*2.0% + 0 = 2.0 L/min
4 + (16*2.0%) = 4.32 mA
3.5%
20 L/min
800 L/min (800-20)*3.5% + 20 = 27.3 L/min 4 + (16*3.5%) = 4.56 mA
3.5% up-side-down
800 L/min 20 L/min
(800-20)*3.5% + 20 = 27.3 L/min 20 - (16*3.5%) = 19.44 mA
7.6 TUNE MIN (4MA)
Use this setting to precisely tune the minimum analog output value (initial
value is 4 mA). This value can differ slightly due to ambient influences such
as temperature.
Before tuning the signal, make sure the analog signal is not being
used for any application.
After pressing PROG, the current will be about 4 mA. The current can be
increased / decreased with the arrow-keys and is directly active. Press
PROG to store the new value.
