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
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


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