#04-4, M1S: Four Opto-Inputs, Common Ground

Function: Four opto-couple inputs with the (–) terminal connected to the system ground, independent (+) terminals

Form factor: M1S

Category: Input module

Special needs: ---

Power requirements: 5V/40mA

Mates with: #19, #20, #21 (limited use)

See also: #04-1, #04-2, #04-3, #04-05, #04-06, #04-07, #04-08, #54

Details

If no external resistor is added, these inputs activate at about 2V. Forward current should not exceed 10mA, which caps the maximum input voltage at about 5V. Add external resistors if you need to apply a higher input voltage.

Note that these are not "isolated inputs" — they share the ground line with the rest of your system. Still, the optical stage isolates your system from noise, electrostatic discharge (ESD), spikes, and other external influences.

Combine Tibbit #04-4 with terminal block devices — #20 (nine terminal blocks) or #21 (four terminal blocks).

LEDs

There are four green LEDs connected to the four control lines. The LEDs light up for the LOW state of the control lines (i.e., when current passes through the diodes of the opto-couplers).