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What is the Difference Between a Line Driver, Open Collector, and Push-Pull Quadrature Encoders and Which One Should I Use?



Hardware: Multifunction DAQ (MIO)>>M Series

Problem:
I want to use a quadrature encoder with my M Series DAQ card. What is the difference between line driver, open collector, and push-pull and which one should I use?

Solution:
Line Driver
A line driver is a sourcing output. When in the on state, a line driver will supply Vcc. In the off state, a line driver will float. Because of this, a sinking input is required for proper operation. Please refer to the table below for a simple example of a line driver.

Open Collector
An open collector is a sinking output. In the off state, an open collector will supply a path to ground. When in the on state, an open collector will float. For proper operation, a sourcing input is required. Please refer to the table below for a simple example of an open collector.

Push-Pull
A push-pull output is a combination of a line driver and an open collector. In the off state it will supply a path to ground and in the on state it will supply Vcc. Please refer to the table below for a simple example of a push-pull output.




Line Driver Open Collector Push-Pull



Which Type of Quadrature Encoder Should I use with my M Series card?
A Push-Pull quadrature encoder is recommended, because the M Series card works best when it is constantly driven. As mentioned above, the Push-Pull configuration does not float, it is always suppling Vcc or ground, which is why it will work best with an M Series card.

Related Links:
Knowledgebase: How Do I Use My Quadrature Encoder with My Data Acquisition Device?

Attachments:


Push-Pull.gifLineDriver.gifOpenCollector.gif


Report Date: 03/11/2005
Last Updated: 04/01/2009
Document ID: 3JAF2BVB

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