Newsgroups: comp.robotics
Path: brunix!sgiblab!sdd.hp.com!swrinde!cs.utexas.edu!uunet!butch!NewsWatcher!user
From: farnham@lmsc.lockheed.com (Greg Farnham)
Subject: Sensing stuck bot with motor current/L293E
Message-ID: <farnham-141293175707@129.197.52.35>
Followup-To: comp.robotics
Sender: news@butch.lmsc.lockheed.com
Organization: CIEM
Date: Wed, 15 Dec 1993 02:09:34 GMT
Lines: 29

Here is a possible option for sensing a stuck robot via the motor current.


The SGS databook (1/84) for the L293B also describes an L293E.  The L293B&D
are 16pin dip motor driver chips which are used in the 6.270 MIT board.  
The L293E is a 20 pin dip which adds a SENSE pin for each of the 4
channels.  Here is a quote from the book:

"Additionally, the L293E has external connections to the lower emitter of
each driver, permitting the connection of sensing resistors, for switchmode
control."

Doesn't this mean that the SENSE pin can be used to detect too high of a
current?


The schematic of the chip states that the for the L293B the SENSE pins are
internally connected to ground.


I found an L293C (20 pin dip) at a surplus store.  I could not find mention
of it in the data books I checked.  I assumed it was similar to the L293E
(both 20 pin).   I hooked it up like an L293B or D and grounded the SENSE
pins.  It didn't work.

Does anyone have any information on the L293C?  Was my assumption wrong?

Greg Farnham
farnham@lmsc.lockheed.com
