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Configuration and Use Manual 73
Configuring Outputs
Configuring Batch Configuring Process MonitorConfiguring OutputsConfiguring Events
Figure 8-4 50% duty cycle
If Maximum Pulse Width is set to a non-zero value, the duty cycle is controlled by the crossover
frequency:
• At frequencies below the crossover frequency, the duty cycle is determined by the pulse width
and the frequency.
• At frequencies above the crossover frequency, the output changes to a 50% duty cycle.
The crossover frequency is calculated as follows:
You can change the setting for Maximum Pulse Width so that the Series 3000 device will output a
pulse width appropriate to your receiving device:
• High-frequency counters such as frequency-to-voltage converters, frequency-to-current
converters, and Micro Motion peripherals usually require approximately a 50% duty cycle.
• Electromechanical counters and PLCs that have low-scan cycle rates generally use an input
with a fixed non-zero state duration and a varying zero state duration. Most low-frequency
counters have a specified requirement for Maximum Pulse Width.
Note: For typical applications, the default pulse width is used.
Note: If you are using the Freq = Flow output scale method, and you set Maximum Pulse Width to a
non-zero value, Micro Motion recommends setting the frequency factor to a value below 200 Hz. See
Section 8.5.1. If you are using the Pulses/unit or Units/pulse output scale method, Maximum Pulse
Width must be set to a value that allows crossover to occur.
Example
The frequency output is wired to a PLC with a specified pulse width
requirement of 50 ms. The crossover frequency is 10 Hz.
Solution:
• Set Maximum Pulse Width to 50 ms.
• For frequencies less than 10 Hz, the frequency output will have a
50 msec ON state, and the OFF state will be adjusted as required.
For frequencies higher than 10 Hz, the frequency output will be a
square wave with a 50% duty cycle.
Crossover frequency
1
2 max pulse width×
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