VELMEX VXM-1 - I;O Electrical Specifications

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I/O Electrical Specifications

Appendix K

All User I/O inputs and outputs are TTL levels (0 to +5VDC.)

Inputs have a 2200 ohm resistor to +5VDC, and are activated by connecting to 0V.

NOTE: When Input 4 (Stop) is held low (0V) program will not run.*

Outputs are normally low, and can sink and source 20 mA max.

Limit switch inputs are optically isolated. Limit inputs operate on 24VDC through a 10K

ohm resistor to power the LED in the optical isolator (see Appendix N.)

The +5VDC on I/O,2 is intended for use with additional analog input circuitry. Current

draw should not exceed 75mA.

CAUTION:

Optically isolated relays should be used on all user I/Os to insure long term reliable

operation.

Never directly connect a VXM I/O to an inductive load, any device that is not within 10 feet

of the VXM, or anything not powered at the same AC source.

Damage due to improperly interfacing VXM controllers to other devices is not covered

under the warranty.

As a minimum precaution against electrostatic discharge (ESD) damage follow these

guidelines:

1. Provide the shortest conductive path possible to earth ground from user

designed panels or enclosures that have switches or buttons the operator will

come in contact with.

2. Use metal panels and enclosures to house buttons or switches electrically

bonded to a protective earth ground.

3. Use shielded cables on all VXM I/O.

4. If no other protective earth ground is available, use the earth ground on the

VXMs Auxiliary I/O connector shell or connector shell on shielded cable.

* New feature: Only on VXM firmware versions 1.21 & up