Question

What are "Push Pull" and "Totem Pole" outputs? Why don't they have a differential output?

Answer

Looking at the A and A not channel, the optical sensor internal to the encoder is comparing the two. If A's light amount is greater than A not, then A is high. When A is less than A not, then A is low. The same reasoning defines channel B. This process is called "Push Pull."

A "Totem Pole" output is the same as a "Push Pull" output. The big difference is the ability of the "Totem Pole" to handle sinking or sourcing less current than the "Push Pull." It is confusing because the other factor is the amount of voltage usually used to define the difference between the two. "Totem Pole" usually uses 5vdc, where as the "Push Pull" follows the input voltage. Our encoders have a range of 5-30vdc, so you will see the output referred to as both.

Our encoders that have "Totem Pole" outputs are technically categorized as open collector NPN style outputs. The only styles of differential encoder (5vdc) are our TRD - S/SHxxxx-VD models.

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FAQ Subcategory: None

This item was last updated on 2017-12-01
Document ID: 825

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