Digital I/O

Scientific experiments or industrial applications require the control of relays, valves or other devices with digital inputs and outputs. Discrete voltage or current levels represent digital signals. The TTL logic family represent logic low for voltages between 0 V and 0.8 V and logic high for voltages from 2 V up to 5 V. The CMOS logic family specify the logic low state from 0 V to 1.3 V and the logic high state from 3.7 V to 5 V. Harsh environments require higher signal-to-noise ratios to reduce error-proneness. Therefore, voltage levels of up to 24 V are commonly used.

General Purpose I/Os

In order to meet the requirements of many scientific and industrial applications, general purpose digital input and output lines are used. The DIO01 Octal Digital I/O Device is a versatile and easy-to-use octal, bidirectional digital I/O module. Each of the eight channels can individually be configured as input or output and is compatible with 5 V TTL / CMOS and 3.3 V LVTTL / LVCMOS voltage levels. Custom timers, counters, pulse generators or digital communication protocols like the widespread SPI bus system can easily be implemented in software. For higher voltage levels up to 24 V, the  DIO02 Octal Digital I/O Device can be used instead which offers open collector inputs or outputs. It is therefore not even required that all channels share the same voltage levels.

Rotary and Linear Position Encoders

The rotary or linear position encoder is an electro-mechanical device that converts the angular linear position of an axle to an analog or digital signal. In particular Gray code encoders use binary counting to provide an absolute digital value and can be connected to general purpose I/O modules. For velocity encoders, the  CNT01 Quad Quadrature Encoder can be used which supports up/down counting mode to detect impulses of an arbitrary clock source as well as the quadrature encoder mode.

Digital Actuators

In a variety of applications electro-mechanical relays, electrical or electro-pneumatic valves, long transmission lines or other digital transducers need to be controlled. Voltages up to 24 V or more are required. The  DO01 Octal Digital Output Buffer can directly interface these devices and can even drive moderate-power DC motors. If high-power electrical or electro-pneumatic valves, heaters or AC / DC motors and other high-power devices shall be controlled, the  DO02 Octal SPST Relay Module can be utilized. This device features eight isolated, independently controllable channels with up to 250 VAC / 3 A each. The fast switching times of less than 2 ms enable fast and reliable control.