# Output type of incremental rotary encoder

I have been trying to choose incremental rotary encoder for speed control of three phase induction motor. My problem is that I am not sure what type of output should I choose. There is following quadrature encoder interface (please see the enclosure - signals from encoder are connected to terminals 1,2,3 in J9) on my control board. I don't know whether this interface is intended only for incremental rotary encoder with open collector output or it is possible to use different output types. Can somebody give me an advice. Thanks in advance.

I have found an encoder which is sufficient in terms of shaft diameter, supply voltage and output type. There are two parameters that are confusing for me in datasheet. The first one is maximum current requirements 180 mA. I suppose that this current is the maximum current that can be sink by the encoder's output transistor. In my case the transistor must sink $\frac{5\,V}{4.7\,k\Omega}=1.06\,mA$. Could this be a problem? The second confusing parameter is output load $50\,mA$ (including $3.3\,k\Omega$). What does this parameter mean? ($\frac{5\,V}{3.3\,k\Omega}\neq50\,mA$). Here is the datasheet of chosen encoder: enter link description here

• Please include links to any parts referenced in your post and repost that image - properly sized and cropped - so that it's legible to any future readers. That looks like an incremental encoder with open collector outputs. For speed monitoring you just need one output. – Transistor Jun 23 '16 at 8:07
• Thank you for your reaction. So you mean that I should choose only the encoders with open collector output? – Steve Jun 23 '16 at 8:31
• I think the board is suited for open collector 5V encoder. – Marko Buršič Jun 23 '16 at 8:52

• I have found an encoder which is sufficient in terms of shaft diameter, supply voltage and output type. There are two parameters that are confusing for me in datasheet. The first one is maximum current requirements 180 mA. I suppose that this current is the maximum current that can be sink by the encoder's output transistor. In my case the transistor must sink $\frac{5\,V}{4.7\,k\Omega}$=1.06mA. Could this be a problem? The second confusing parameter is output load 50 mA (including 3.3 k$\Omega$). What does this parameter mean? ($\frac{5\,V}{3.3\,k\Omega}$≠50mA) – Steve Jun 24 '16 at 7:26