Wiring limits

[toomanyhobbies]

First off, Please excuse my complete lack of understanding of electronics   Well, I understand some basic stuff but I'm very unsure of myself and don't want to destroy a very expensive Galil card and ICM 2900.   

Ok, I need to start the wiring on my mill project and I'm having some questions about some basic stuff. I have a ICM 2900 and want to wire the limit and home switches.

Questions...  Should the wiring for the limit and home switches be hooked directly to the Galil ICM 2900 or is there some sort of optoisolation that needs to be placed in between the ICM2900 and the actual limit switch circuit? If hooked directly to the ICM, is there any built in protection to the Galil card or the computer? Do I need to provide the limit switch circuit with a external power source? Do I provide power through a pull up resistor? And if so, how is that wired into the limit switch circuit?

Any help would be greatly appreciated, Thanks

[smurph]

There are two versions of the ICM-2900.  A regular one and then one with optical isolation for the outputs.  The isolated one has a white tag on top that says "OPTO".

See http://www.galilmc.com/support/appnotes/optima/note1427.pdf for the OPTO optioned ICMs and connection outputs.

See http://www.galilmc.com/support/appnotes/optima/note1419.pdf for connection outputs for the non OPTO ICMs.

The Optima controllers have optically isolated inputs.  A power supply for the limits switches should provide + to LSCOM on the ICM and the switch should be connected to - on the power supply and the appropriate limit switch input. (Up to 24v on LSCOM and INCOM)

The Econo series controllers have TTL inputs that are pulled up internally to 5v.  A normally open limit switch should be placed between GND and the appropriate limit switch input on the ICM.

Check the manual for your controller to determine which style of inputs you have (TTL or OPTO).

Steve