Digital Inputs 

Digital Inputs

The FAC-2100 has ten total digital inputs with following capability:

• Eight Standard Digital Inputs that can read a wide voltage range which includes 200VDC and 120VAC signals.
• Two Universal Digital Inputs that can read digital waveform signals with voltages up to 28VDC. These channels allow the FAC-2100 to read frequency and duty cycle and can be paired for quadrature decoding.

Basic On/Off Mode

Both the Universal and Standard Digital Inputs can read in basic on/off mode. In this mode the controller determines if the input signal is present or not.

Frequency and Duty Cycle Measurements

Universal Digital Inputs can process a waveform and determine the signal's frequency and duty cycle.

Quadrature Decoder

Signals that are quadrature encoded provide direction and speed of an attached sensor from two signals (typically called Channel A and Channel B). The Universal Digital Inputs can be used as a pair to decode these types of signals with Channel A going to D_UIN1 and Channel B to D_UIN2.

If the quadrature encoder output is using a driver such as an RS-485 or RS-422 transceiver, it is recommended that each D_UIN+ and D_UIN- signals be terminated with an impedance that matches the transmission line. To accomplish this, install a resistor (typically around 120 ohms) across both the D_UIN1 and D_UIN2 plus and minus terminals.

Wiring

Each digital input channel consists of an opto-isolated LED / transistor pair with a dynamic drive circuit that permits a wide input voltage range to be applied. Each of the modes described above utilize the same wiring configuration.

Suggested Digital Input Wiring to a Mechanical Switch

Notes: The suggested wiring above uses digital input 1. Any digital input could be wired in a similar configuration. Also, because the digital inputs are opto-isolated, the circuit could have been wired with a jumper between pins b and J with wires from K and c connecting to the switch.