Incremental encoders with 9411 in scan mode

[Yixiao-uncle]

Hi.

I developped a project to control a plant using a controller NI9067 working in scan mode. Among the devices there is a NI 9411 to acquire pulses from incrmental encoders, so I have just chA and chB from encoder, no Z index, and i need to reset position in order to have the right reading of position. In Specialty Digital Configuration of 9411, the Quadrature function is performed for encoders with A, B and Z index. But I dont have Z index, so how to wire encoders signal to board and how to perform the reset operation?

Attached the vi I developped not in rt target to calculate position and reset procedure

Thank yo for your help

[CorraDIT]

Hi antonio_ferrante,

the pinout of the board is the same, so just use the regular pinout for A and B encoders. As far as the reset, that is what the Z encoder is concerned. You should know the resolution of the encoder and from that you should be able to calculate the zero position. You can then use that to move the shaft back or forth until you reach it.

Is that what you were asking?

[Yixiao-uncle]

Hi CorraDIT:

concerning the device pinout, it was what i were asking. 

Moreover I need to acquire 2 single ended encoders system, so is the following the right pinout?

Encoder 1

Channel A: DI0a

Channel B: DI1a

Encoder 2:

Channel A: DI3a

Channel B: DI4a

In Quadrature Specialty digital configuration the output is position in count but this is not very clear to me: is that the number of revolution?

thank you for your help.

[CorraDIT]

Hi antonio_ferrante,

the pinout of the board is attached. I think it should be pretty straightforward.

[Buechsenschuetz]

http://www.ni.com/white-paper/4763/en/

The number of counts per revolution is 4 times the number of lines per revolution as specified in the encoder specs. 

You should always use a hardware reset position (like a Z signal) to detect the reference position. Counting up and down is not always reliable, since pulses may get lost and since the normal uncertainty of +/- 1 when counting may accumulate.