Yokogawa digitalYEWFLO (DY) - Manual (Page 64)

MAINTENANCE
IM 1F2B4-01-YIA
Page 68
4.1.10 Scaling the pulse output
Before setting the pulse rate be sure that the YEWFLO has been properly set to pulse output mode. The
pulse output of the YEWFLO may be configured as a scaled or unscaled pulse output. Follow this
procedure to set the pulse scaling. Use scaled pulse to scale the output to pulses per engineering unit per
B51 Flow span units. Use unscaled pulse (UNSC*1, UNSC*10 or UNSC*100) for maximum pulse
resolution. Output will be 1, 10 or 100 pulses output for each input pulse. Use the K-factor to convert
unscaled units to volume units.
Setup of pulse output
BT200 handheld terminal BT100 handheld terminal
C: SET 2 Scroll through the menus to the
C: SET 2 , then press ENTER. Depress the MENU key until
the C: Set 2 menu appears.
C02: pulse rate
E +2 Scroll down to C02: pulse rate
and press ENTER. Press p r m tr key to move
to parameter C02: pulse rate .
Select from the list the desired
pulse rate factor, press
ENTER twice. Use the INC or DEC key to
select the desire pulse rate
factor. Press ENT twice.
The available options for pulse rate include scaled and unscaled
rates.
Examples:
E 0 1 pulse equals one unit of flow
(10
0 ), units same as flow span.
E +2 1 pulse equals 100 units of
flow (10
2 ), units same as flow
span.
E - 2 1 pulse equals 0.01 units of
flow (10
-2 ), units same as flow
span.
There are three special unscaled settings designed to maximize
resolution:
UNSC * 1 1 pulse in, 1 pulse out
(Unscaled)
UNSC * 10 1 pulse in, 10 pulses out
(Unscaled)
UNSC * 100 1 pulse in, 100 pulses out
(Unscaled)
Set this parameter such that the maximum count or pulse rate does not exceed 6,000 Hz at max flow span.
Note: Gas Expansion Correction Factor in % reading = (-5.70833 x E-4 x V 2 ) - (5.83333 x E-4 x V);
Where V = Average measured uncorrected velocity in m/sec