View Single Post
  #82   Spotlight this post!  
Unread 10-05-2012, 00:57
techhelpbb's Avatar
techhelpbb techhelpbb is offline
Registered User
FRC #0011 (MORT - Team 11)
Team Role: Mentor
 
Join Date: Nov 2010
Rookie Year: 1997
Location: New Jersey
Posts: 1,624
techhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond reputetechhelpbb has a reputation beyond repute
Re: TI and future Jaguars

Quote:
Originally Posted by Tristan Lall View Post
I think he means that the disable signal is either an element of the control signal (neutralizing PWM to disable is "in-band"), or a separate signal (neutralizing via digital I/O + PWM is "out-of-band").
Basically.

In telecommunications when we are doing in-band management we are managing something often over the same bandwidth that infrastructure is providing (SSH for example). When we do out-of-band management we are providing some alternative communications infrastructure to manage devices (a dial-up modem to a Cisco console port for example).

If you can somehow communicate over the CAN bus to the electronic motor control your intention to disable it you are operating in-band.

If you add a digital I/O wire to communicate the disable you are operating out-of-band (there's probably no other communications on that disable wire, or as much of my industrial stuff would call it the e-stop). The addition of the alternate communications infrastructure makes it out-of-band.

Stopping PWM might be considered in-band signaling in some ways, but personally, the absense of signal into a motor control to me should just naturally make it stop. Just as if you powered it up on a bench to test with no signal input. That's really a fault condition to me because generally with PWM there's a certain pulse width that's the neutral position for the speed control and in the absense of even the base frequency you may as well have left it floating.

Last edited by techhelpbb : 10-05-2012 at 00:59.
Reply With Quote