How Many Counters Does Each Type of Counter Input or Output Task Take?

Primary Software: Driver Software>>NI-DAQmx
Primary Software Version: 7.0
Primary Software Fixed Version: N/A
Secondary Software: N/A

Problem:
I am trying to use a DAQmx Create Channel VI for a counter, but I don't know how many counters I need.

Solution:
The following table shows the number of counters required for each of the following tasks. For some measurements, the number of counters depends on another setting. In these cases, all the possible settings that affect the number of counters have also been included.

Counter Input

Counter Measurement	Polymorphic Instance	Number of Counters
CI Freq: Low Frequency with 1 Counter		1
CI Freq: High Frequency 2 Counters		2
CI Freq: High Frequency with 2 Counters		2
CI Period: Low Frequency with 1 Counter		1
CI Period: High Frequency with 2 Counters		2
CI Period: Large Range with 2 Counters		2
CI Count Edges		1
CI Pulse Width		1
CI Semiperiod		1
CI Angular Encoder		1
CI Linear Encoder		1
CI Two-Edge Separation		1
CI GPS Timestamp		1

Counter Output
There are three different counter pulse output task types, CO Pulse Freq, CO Pulse Time, CO Pulse Ticks, but they all use the same number of counters based on how many pulses you are generating. You specify the number of pulses to generate with the DAQmx Timing VI. Finite pulse generation requires two counters because one counter gates the other to produce the finite pulse train.

Number of Pulses Generated	Polymorphic Instance	Number of Counters
One		1
Continuous (Infinite until the end of the task)		1
Finite		2

Note: Single or finite pulse generation can be retriggerable and do not change the number of counters used.

Report Date: 05/01/2008
Last Updated: 07/17/2008
Document ID: 4L0A62E9

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