If pulse width is set to 100 ms, the maximum output is 5Hz; for a pulse width of 0.5 ms, the
maximum output would be 1000Hz (at the maximum frequency output there is a 50%
duty cycle).
Pulse width
Minimum period (50% duty
cycle)
Maximum frequency
100 ms
200 ms
= 5
Hz
1
cycle
200
ms
0.5 ms
1.0 ms
= 1000
Hz
1
cycle
1.0
ms
To achieve the greatest maximum frequency output, set the pulse width to the lowest
value that is consistent with the requirements of the pulse output power source, pulse
driven external totalizer, or other peripheral equipment.
The maximum flow rate is 10,000 gpm. Set the pulse output scaling such that the
transmitter outputs 10,000Hz at 10,000 gpm.
Pulse Scaling =
Flow Rate (gpm)
(60
×
)
(frequency)
sec
min
Pulse Scaling =
10,000 gpm
(60
×
)
(10,000 Hz)
sec
min
Pulse Scaling = 0.0167
gal
pulse
1 pulse = 0.0167 gal
Note
Changes to pulse width are only required when there is a minimum pulse width required for external
counters, relays, etc.
The external counter is ranged for 350 gpm and pulse is set for one gallon. Assuming the
pulse width is 0.5 ms, the maximum frequency output is 5.833Hz.
Frequency =
Flow Rate (gpm)
(60
×
)
)
(
pulse scaling
sec
min
gal
pulse
Pulse Scaling =
350
gpm
(60
×
)
sec
min
1
gal
pulse
Frequency =
5.833
Hz
The upper range value (20mA) is 3000 gpm. To obtain the highest resolution of the pulse
output, 10,000Hz is scaled to the full scale analog reading.
Advanced Configuration Functionality
92
Rosemount
®
8732EM Transmitter with HART Protocol Reference Manual
Summary of Contents for Rosemount 8732EM
Page 2: ......
Page 6: ...Contents iv Rosemount 8732EM Transmitter with HART Protocol Reference Manual ...
Page 10: ...Safety messages 4 Rosemount 8732EM Transmitter with HART Protocol Reference Manual ...
Page 14: ...Introduction 8 Rosemount 8732EM Transmitter with HART Protocol Reference Manual ...
Page 30: ...Sensor Installation 24 Rosemount 8732EM Transmitter with HART Protocol Reference Manual ...
Page 92: ...Operation 86 Rosemount 8732EM Transmitter with HART Protocol Reference Manual ...
Page 158: ...Maintenance 152 Rosemount 8732EM Transmitter with HART Protocol Reference Manual ...
Page 214: ...Product Certifications 208 Rosemount 8732EM Transmitter with HART Protocol Reference Manual ...
Page 217: ...Wiring 8732EM using combination cable Figure C 2 Wiring Diagrams Reference manual 211 ...
Page 222: ...Wiring Diagrams 216 Rosemount 8732EM Transmitter with HART Protocol Reference Manual ...
Page 253: ...Implementing a Universal Transmitter Reference manual 247 ...