Instruction Manual
7-91
IM 01R04B04-00E-E 8th edition March 01, 2011 -00
All Rights Reserved. Copyright © 2003, Rota Yokogawa
10% higher is recommended because the duty
cycle is not always exact 50%. For certain pulse
widths the duty cycle at max.Q is larger than 50%
so fewer pulses can be generated. These pulses
are delivered later when the owrate is again
below max.Q minus 10%. To avoid this situation it
is recommended to keep the owrate always 10%
below max.Q.
Flowrate : 11 t/h
Pulse unit : kg
Pulse rate : 0.1 kg/P
Time factor (related to s) = 3600 P/h
Lowest pulse width
= 0.5 s*pulse rate* time factor/ max. ow rate
= 0.5 s*0.1 kg/P *3600 P/h /(11000 kg/h)
= 16.4 ms
→ customer should select 10 ms pulse width or lower.
Max. Q = 18000 kg/h
11000 kg/h < 18000 kg/h - 10%
Pulse width = 10 ms
Pulse rate = 0.1 kg/P
For a rst orientation the max. Q for certain pulse
widths and units for a pulse rate of 0.1, 1 and 10
are given in the table 7-1.
Max. ow restriction :
Set as a pulse output the pulse length is constant
but the time between the pulses varies. Even at
constant ow the time between the pulses might
vary because the microprocessor has to nd a
suitable gap in its timing to send the pulse.
Typical pattern for frequency output :
Typical pattern for pulse output
(50 ms; 0.1 kg/P; 2580 kg/h) :
Because the duty cycle of pulses is max. 50%,
the max. owrate is restricted by the pulse width,
the unit and the pulse rate :
Max. ow rate =
1s/(pulse width*2) *pulse rate *time factor
Max. Q should be calculated in kg/min
Pulse width = 50 ms
Pulse rate = 0.1 kg/P
Time factor (related to s) = 60 P/min
Max. Q = 1s/(0.05s *2) *0.1kg/P * 60P/min = 60kg/min
t
flow
Max flow from pulse width, unit, rate
this amount will
be lost
t
flow
Max flow from pulse width, unit, rate
Grey zone
this amount will
be lost
F3.EPS