Z reference output on encoder

[Black Forest]

Is there a way to test for the Z reference signal on an encoder? I have some closed loop steppers and the documentation is less than stellar. The encoders are supposed to have the Z reference but I am not sure. So how can I test for the Z on the bench? This would be used with the Centroid Acorn on a mill.

[RB211]

Try the CZ open collector, when it trips, it should complete the circuit to GND, if I understand it correctly. I don't use open collectors. The OZ+- I believe is for a differential output, not Z reference.

[Black Forest]

Do you have any idea how I would set this up on the Acorn? I did a lot of searches on the Acorn forum but only a reference to DMM ZRI. It shows how to wire it but not how to set up Acorn.
I think I have to select ZRIhome to an input. This might move the axis to the limit and then back off until the Zri triggers the extra input and then it sets that axis to home. Not sure and the search on the Acorn forum sucks big time. Keith makes a reference to a .pdf and gives the number of the .pdf but a search for that turns up nothing.

[RB211]

Do you have any idea how I would set this up on the Acorn? I did a lot of searches on the Acorn forum but only a reference to DMM ZRI. It shows how to wire it but not how to set up Acorn.
I think I have to select ZRIhome to an input. This might move the axis to the limit and then back off until the Zri triggers the extra input and then it sets that axis to home. Not sure and the search on the Acorn forum sucks big time. Keith makes a reference to a .pdf and gives the number of the .pdf but a search for that turns up nothing.

I haven't done that yet with the Acorn but I believe you are on the right track. Only concern I have is that the Z output is open collector and your machine is wired NC, correct? I am sure this is all much simpler in actual practice.
I believe Cntrl i brings up the diagnostic screen so you can see the state of the inputs change if you move the stepper to test.

[MaxHeadRoom]

If you don't have a 'scope, it can be done with a meter, you measure from the common terminal to the Z pulse pin and VERY slowly turn the encoder until you see that 5v on the pin, it will be very brief!
Encoders come with the 2 supply terminals and either three, square waves on A,B,Z terminals or they can have complimentary pulses A, /A, B, /B, Z, /Z
Very few do not have the Z pulse included. It has one pulse/rev.

[genea]

BF, the timing of pins OC+ (27) and CZ (29) is identical but before you can see the output on CZ (29) with an o-scope or meter you must add a pull up resistor to some positive voltage. That positive voltage can be +5V, but it can also be higher for better noise immunity. Open collector (OC) devices are usually rated for up to +24 or 28 V but before using a voltage that high check the specifications of the OC circuit and the input requirements of the circuit it will be driving.

In addition to better noise immunity at higher voltages OC outputs also offer the possibility of connecting multiple OC outputs to a single signal line.

[MaxHeadRoom]

IIRC the 26LS31 has RS-422 drivers and is rated for 5v, if so it does not require a pull-up?

[genea]

IIRC the 26LS31 has RS-422 drivers and is rated for 5v, if so it does not require a pull-up?

You're right, the 26LS31 doesn't require pull ups. I got confused by RB221s posts referring to the CZ (29) open collector output. That signal does require a pull up. and may be used to drive a higher voltage device, such as a relay.

[MaxHeadRoom]

what is the 26ls31? And where did you find it?

The 26LS31 is a RS422 driver IC and is shown in your OP attachment and on the motor manuf web site
It is a common driver IC for encoders.

[kf2qd]

Z+ and Z- would also be easy to monitor with a meter. Look for the voltage to invert. Z is used in combination with you home switches to find home home switch could vary several steps, use it with the Z and ypu have it down to 1 pulse.

[macona]

RS-422 is usually around a 2.7-3v logic signal high when running the chip off of 5v. You have losses internally. You can get little adapters that do differential to single ended, I also made some of my own and have extra boards, I could put one together for you. Its very simple, 26LS32 receiver chip, decoupling cap, and a voltage reg if you are running it off anything above 5v. It just outputs standard 5v TTL level signals. Sometime you can just use one wire of the differential pair referenced to the ground connection, it will depend on what it is feeding and if it meet the minimum logic high signal level.

[RB211]

OZ+ and OZ- is not to be confused with CZ which is the single pulse per rev

[skunkworks]

there is going to be one pulse per rev... CZ is a single pulse but open collector.. OZ+ and OZ- are single pulses but inverted of one-another..

High count encoders are going to be very tricky to catch a index with a volt meter. Better to use a scope.