View unanswered posts | View active topics It is currently Mon Aug 03, 2020 10:54 pm

Reply to topic  [ 3 posts ] 
Use a 500CPR Encoder with Cortex 
Author Message

Joined: Tue Dec 07, 2010 11:51 am
Posts: 4
Post Use a 500CPR Encoder with Cortex
I'm using an optical quadrature encoder with 500 CPR. With TTL Squarewave output.

I tried to use the embedded encoder input function but failed.
I get values but not reasonable values. Probably because the VEX encoder has a lower CPR?
The encoder has two outputs with low 0V and high 5V.

So is it possible to make some changes in the embedded encoder function or create a new one that works with our encoder?


Tue Dec 07, 2010 12:35 pm
Site Admin
Site Admin

Joined: Tue May 15, 2007 9:02 am
Posts: 409
Post Re: Use a 500CPR Encoder with Cortex
Currently, we only support the official VEX encoders in firmware, which provide 360 CPR. There's some technical info regarding the sensors in this document: ... r-inst.pdf

Jesse Flot
CMU Robotics Academy
ROBOTC Support

Tue Dec 07, 2010 4:07 pm

Joined: Wed Dec 08, 2010 3:20 am
Posts: 6
Post Re: Use a 500CPR Encoder with Cortex
Hello. I'm working with norsmi, thought I'd clarify.

We are using a non-VEX encoder that seems to be generating reasonable values.
Not 100% sure, but I think we have the latest firmware (it came with RobotC 2.30)
When connected to ports designated by the Sensor/Motor Setup as Quadrature encoders, these are the results:
•when the shaft is turned at more or less constant speed, SensorValue[..] oscillates between 2 adjacent values
•when the shaft turning speed is changed, the encoder value jumps to a new value.

This would indicate that SensorValue[] returns a speed measurement (wierd!)... except that the connection between speed and SensorValue[] reading seems non-existant or obscure.
Any help in interpreting these values would be appreciated =)

[edit] It seems our Cortex was merely having a bad day. Starting up the same code a few days later, we get reasonable values out of the encoder's SensorValue[].
Thanks anyway =)

Wed Dec 08, 2010 3:57 am
Display posts from previous:  Sort by  
Reply to topic   [ 3 posts ] 

Who is online

Users browsing this forum: No registered users and 1 guest

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  

Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group.
Designed by ST Software for PTF.