LOGIC INPUTS
Sixteen Logic Inputs are available on a rear panel 25-pin Sub-D (female) connector. Logic Inputs allow remote control of the MG2500 via external circuits, such as switches, contact-closures, active driver circuits, and/or ‘open-collector’ logic outputs. From the factory, Logic Inputs 1~16 have no pre-programmed function. However, each Logic Input may be assigned different ‘actions’ using the MG2500 software and serial cable provided with the unit (see Setup on pg. 10). Since Logic Inputs are controlled by switches, contact-closures, etc., each Logic Input may be assigned two functions (one for switch ‘closed’ and one for switch ‘open’).
Logic Inputs have the following pin assignments (right-to-left & top-to-bottom): Pins 1~16) Logic Inputs 1~16; Pins 17~25) Ground.
logic inputs | pin numbers |
| |
logic #1~16 | pin #1~16 |
| |
ground | pin #17~25 |
| |
When nothing is connected to a Logic Input, an internal pull-up resistor keeps it at a ‘high’ idle state (+5.0 VDC). The Logic Input is activated when its input goes ‘low’ (less than +0.8 VDC), and is de-activated when its input goes ‘high’ (greater than +2.4 VDC). A Logic Input is controlled in one of three ways: 1) Use an NPN style ‘open-collector’ logic output from an external device (such as another product or third-party controller) to short the Logic Input to ground. 2) Use a switch, relay, or other contact-closure (such as from a third- party controller) to short the Logic Input to ground. 3) Use an active TTL output driver circuit (such as from a third-party controller) to actively drive the Logic Input to a ‘high’ or ‘low’ state.
Multiple contact-closures or ‘open-collector’ logic outputs may be wired in parallel to a single Logic Input (see diagram below). Logic Outputs and contact-closures should be rated for at least 5 Volts / 1mA operation. Low-current / dry-contact closures are recommended for reliability. Active output driver circuits should not exceed a signal range of 0~5 Volts DC, and should have a minimum pulse width of 100 milli-seconds. Logic Input impedances are approximately 10k ohms.
multiple switches to single Logic Input
