RE: [CAD_CAM_EDM_DRO] E-Stop wiring

The way I've designed the E-Stop buttons to work, on the Bridgeport I'm
re-building, is through an input to the parallel port. The E-Stop will kill
all output to my stepper drives. In addition, on an E-Stop, the parallel
port will de-activate the "Bridgeport control relay" pin on its output (I
used pin #14 in my case, which has been converted to 12 volts DC). This, in
turn, is connected to the coil of a 12 volt DC, 3 pole double throw relay.
On one pole of the relay, I have one side of the Bridgeport motor starter
coil across a normally open contact. The other poles operate an number of
safeties (to prevent pneumatic brakes being applied while the motor was
running, etc.) and idiot lights.

I felt that adding the control relay provided me with a failsafe to prevent
the milling machine from running unless the software specifically called for
it and simultaneously provide logic control for a number of other functions,
including an E-Stop capability) at a minimal increase in cost and
complexity.

Regards,
Jeff


-----Original Message-----
From: Lloyd Leung [mailto:lloyd@...]
Sent: Wednesday, March 05, 2003 7:21 AM
To: CAD_CAM_EDM_DRO@yahoogroups.com
Subject: [CAD_CAM_EDM_DRO] E-Stop wiring


How should I wire my e-stops?





I believe my only options are:

1.) E-stop switch connected to the parallel port. [software polled,
TurboCNC]

2.) E-stop switch between the capacitor and the fuses. Star pattern
from e-stop, instead of the +'ve terminal on the CAP.

i. DC Capacitor +'ve

ii. E-stop

[Repeat below as many times as needed]

iii. Fuse

iv. Gecko Pin 2 (with 470 uF cap)

3.) E-stop switch between Gecko Pin 1 and the -'ve on the capacitor



What is the best option? And any reason for it?



I have a bleeder resister on the CAP.



I'd just like to know how others have setup their E-stops.



Thanks.

Lloyd,

Toronto, Ontario.