Voltage encoder with 7i97T board

More
09 Jun 2024 11:50 #302674 by greg23_78
I currently have a 7i97t board, and I would like to connect a pin encoder to my board.

my encoder must be powered in 10-30V dc (i don't know the encoder output voltage), it's single-ended wiring.

i've seen that the 7i97t board can handle input voltages of 12V single-ended.

is it too risky to cable my encoder on my board with 10V voltages or should I cable it with a voltage divider?

My encoder is currently connected like this:

VCC - A - B - /Z - Ground

should I keep it as is (no importance) or should I change the wiring of the /z to z index?

Please Log in or Create an account to join the conversation.

More
09 Jun 2024 14:17 #302678 by PCW
I would check the output voltage, they might be 5V out or open collector.
The may also be open collector with a pullup resistor to their power supply
(you can test for a resistive pullup by supplying a small load on the output,
say 1K Ohm. and seeing if the voltage output drops significant;y when loaded

How to handle the interface depends on what kind of outputs the encoder has.

 

Please Log in or Create an account to join the conversation.

More
09 Jun 2024 16:27 #302684 by greg23_78
My coder's technical documentation is as follows 

 

 
Attachments:

Please Log in or Create an account to join the conversation.

More
09 Jun 2024 16:43 #302685 by PCW
That's a bit awkward since the low level is only specified to be less than 2V
which is very close to the TTL input threshold.

It would require a voltage divider per pin, say 220 ohms from 7I97T input
to ground and 1K Ohm in series per pin for 24V encoder power

Please Log in or Create an account to join the conversation.

More
17 Jun 2024 19:58 #303199 by greg23_78
When the jumpers are in the left hand position, /A /B /Z is a ground or should i wiring all 220 ohm resistor in ground (24V) ?

Please Log in or Create an account to join the conversation.

More
17 Jun 2024 20:18 #303201 by PCW
The 220 ohm resistors would be connected between the A,B,IDX inputs
and encoder ground (TB1,TB2 pins 3,11,19)


So for example for encoder 0 signal A:

Encoder signal  A --> 1K resistor --> 7I97T TB1.1 (A)
7I97 TB1.1 (A) --> 220 ohm resistor --> 7I97T TB1.3 (GND)

Please Log in or Create an account to join the conversation.

More
18 Jun 2024 18:57 #303293 by greg23_78
and the last question, should i connect the ground of the 24VDC on the encoder ground ?

Please Log in or Create an account to join the conversation.

More
18 Jun 2024 19:09 #303296 by PCW
Yes, the 24V common/negative needs to connect to the 7I97 encoder GND.
 

Please Log in or Create an account to join the conversation.

More
18 Aug 2024 18:49 - 18 Aug 2024 18:51 #308102 by greg23_78
wanting to configure my spindle encoder and reading linuxcnc doc for Spindle Synchronized Motion I found out that the encoder must be connected to mesa card inputs and not to encoder input 5 (7i97T).
Do I have to change my encoder wiring or is it possible to do the same as
# Add the encoder to HAL and attach it to threads.
loadrt encoder num_chan=4
addf encoder.update-counters base-thread
addf encoder.capture-position servo-thread

# Set the HAL encoder to 100 pulses per revolution.
setp encoder.3.position-scale 100

# Set the HAL encoder to non-quadrature simple counting using A only.
setp encoder.3.counter-mode true

# Connect the HAL encoder outputs to LinuxCNC.
net spindle-position encoder.3.position => spindle.0.revs
net spindle-velocity encoder.3.velocity => spindle.0.speed-in
net spindle-index-enable encoder.3.index-enable <=> spindle.0.index-enable

# Connect the HAL encoder inputs to the real encoder.
net spindle-phase-a encoder.3.phase-A <= parport.0.pin-10-in
net spindle-phase-b encoder.3.phase-B
net spindle-index encoder.3.phase-Z <= parport.0.pin-11-in


with the encoder cable on encoder input 5
Last edit: 18 Aug 2024 18:51 by greg23_78.

Please Log in or Create an account to join the conversation.

More
18 Aug 2024 19:49 #308106 by PCW
The 7I97T has 6 hardware encoders, you do not use the software
encoder.  Your sample looks like a parallel port configuration.

I would suggest using MesaCT to create a hal/ini configuration file set.

Please Log in or Create an account to join the conversation.

Moderators: PCWjmelson
Time to create page: 0.105 seconds
Powered by Kunena Forum