User Manual
E018-P
Page 22
FW_E018-P_M_v0301-01_EN
2
FLOWRATE
2.2 TIME
Determines the time interval (sec, min, hour or day) for calculating the
flowrate.
2.3 DECIMALS
Determines the number of decimals for the flowrate.
If the number of decimals are changed in this menu, this will change the
decimal settings for:
●
URV (
7.1: ANALOG OUTPUT > RATE MIN (4MA)
),
●
LRV (
7.2: ANALOG OUTPUT > RATE MAX (20MA)
), and
●
4.7: DISPLAY > RATESPAN
.
Therefore, you should first determine the required decimals for the flowrate.
2.4 K-FACTOR
This value is used to convert the flowmeter pulse signals to a flowrate unit.
The
K-factor
is based on the number of pulses generated by the flowmeter
per measurement unit selected in
2.1: FLOWRATE > UNIT
.
The more accurate the
K-factor
, the more accurate the system.
After pressing PROG, the decimal point will start to flash. The decimal
position can then be changed by pressing the SELECT-key, then press the
CLEAR key to set the digits.
2.5 CALCULATION
The flowrate is calculated by measuring the time between a number of
pulses, for example 10 pulses. The more pulses measured, the more
accurate the flowrate.
●
This setting directly influences the update time for the analog output
(maximum update 8 times a second). If the output response is too slow,
decrease the number of pulses.
●
The lower the number of pulses, the higher the power consumption of
the unit will be (important for battery powered applications).
●
For low frequency applications (below 10 Hz), do not program more than
10 pulses, otherwise the update time will be very slow. For
high‑frequency applications (above 1 kHz), enter a value of 50 pulses or
more.
●
Keep in mind that values higher than 200 in combination with low
frequencies will result in slow updates of the indicated flowrate and
analog output.
2.6 CUT-OFF
Determines a minimum threshold for the required flow. If during this time
less than XXX pulses are generated as set in
2.5: FLOWRATE > CALCULATION
,
the flowrate will be displayed as zero.
The cut-off time has to be entered in seconds. The maximum time is 999.9
seconds (approximately 15 minutes).
2.7 DAMPING
Sets the step-response time of the flowrate measurement. The step-
response time is the time it takes for the displayed value (and thus the
analog output value) to reach 63% of the final value.
For example, when the flowrate increases from 10 to 100 l/s and the
damping is set to 10 seconds, the analog output (and the displayed value)
will increase to: 10 + 0,63 x (100-10) = 66l/sec after 10 sec. Eventually it will
display 100 l/sec.
5.5.3
MENU 3: ALARM
When the unit is configured to transmit the alarm status in
8: RELAY OUTPUTS
, the following settings
determine:
● how the flowrate is monitored.
● the functionality of the transistor outputs D1-D4 and optional relay outputs D5-D6.
For transistor/relay output functions, see
8: RELAY OUTPUTS
.
The flowrate alarms are visible in HART:
A low alarm will set dev.statusbit 14.5.
A high alarm will set dev.statusbit 14.6.