Frequency, Pulse and PWM Outputs
The frequency channel has three modes . The first is straight frequency output in the range of 63…10,000 Hz with 3000
Hz being the typical maximum . The second is a pulse output (one pulse per every defined mass unit) . The third is a pulse-
width modulation (PWM) output that varies the ratio of on time to a set period . The output can be configured for one of the
three modes .
The frequency channel can drive external devices such as rate indicators, batch totalizers and similar devices . Access the
frequency setup parameters through the
Main Menu
>
SETUP > SYSTEM I/O > FREQUENCY SETUP
menu . Selecting
FREQUENCY
SETUP
enters the frequency/pulse out menu .
OTEE:
N
Password level must be Technician or Engineer to change settings .
1 . Assign the parameter to the ID parameter .
2 . Select output mode
PlsOM
(130) .
◊ Frequency
◊ Pulse
◊ PWM
Frequency Output
1 . From the
Frequency Output
menu, enable the pulse/frequency output
FrqOEN
(129) and
EN
(Enable) .
2 . Assign the parameter to use with the frequency output
ID
. The default is the mass flow rate
mFlo
(59) .
3 . Enter
FrqMn
and the minimum value of the assigned parameter
VluMn
.
4 . Enter the maximum frequency
FrqMx
and the maximum value of assigned parameter
VluMx
.
Test Frequency
To test the frequency output at a fixed value, set the output
TstOut
to the desired frequency and enable the test frequency
+AltFrq
(128) . Check that
FrqOEN
and
EN
are enabled . While the test frequency is enabled, the warning message
"6, Freq. out
error"
shows on the transmitter .
Monitor Frequency
To monitor the frequency output, view
FrqOut
(122) .
Pulse Output
1 . From the
Frequency Output
menu, enable the pulse/frequency output
FrqOEN
(129) and
EN
(Enable) .
2 . Assign the parameter to use with the pulse output
PlsID
(131) . The default is the mass totalizer
mTot
(80) .
3 . Enter total amount per pulse in
PlsSze
(132) . The pulse width is fixed at 7 ms . Make sure that the pulse cannot trigger faster
than every 14 ms for a 50% duty cycle at maximum flow rate .
Example: Maximum mass flow rate is 600 lb/min or 10 lb/s, then the minimum pulse size is 0 .14 lb .
10 lb/s * 0 .014 s - 0 .14 lb
If the pulse size or mass totalizer is negative, a warning message shows on the transmitter .
6, Freq . out error
Frequency output is enabled, but it is in test mode or has an invalid setting .
Test
frequency
+AltFrq
(128) is enabled . Minimum frequency
FrqMn
is negative or minimum and
maximum values are swapped .
7, pulse out error
Assigned totalizer is negative or invalid pulse settings . Check the totalizer value and pulse size
PlsSze
(132) for a negative value .
34, Fl low limit
Value of measured parameter is below the minimum value VluMn .
Output Configuration
Page 33
April 2019
CRL-QS-01552-EN-05
