What is the difference between the Digital I/O Expander with Open-Collector Outputs and the Digital I/O Expander with Normally-Open Relay Contact Outputs?
The ENVIROMUX-DI16DO16 Digital I/O Expander with Open-Collector Outputs adds 16 digital inputs and 16 digital open-collector outputs to an ENVIROMUX-2D/5D/16D. The 16 digital inputs can be used to connect passive sensors (do not require power). Door switches, emergency / panic buttons and vibration sensors are some of the many digital input sensors that the expander supports. The 16 open-collector outputs can sink up to 500mA of current to control externally powered devices running on up to 24V DC, such as the Automatic Voice Dialer (runs on 9-18VDC), which is controlled by the ENVIROMUX system. For example, if a temperature sensor that is connected to the ENVIROMUX system detects that temperature has risen to critical levels, the ENVIROMUX system can activate the voice dialer connected to the expander to notify personnel of the issue. Alternatively, the ENVIROMUX-2D/5D/16D auxiliary power supply can be used to power the output devices connected to the Digital I/O Expander.
In contrast, the ENVIROMUX-DI16DOR16 Digital I/O Expander with Normally-Open Relay Contact Outputs adds 16 digital inputs and 16 normally-open output relays to an ENVIROMUX-2D/5D/16D. The 16 digital inputs share the same restrictions as the above. The key difference lies in the 16 normally-open output relays that have a voltage capacity of 125VAC, enabling them to support externally powered devices that require a much higher voltage, such as solonoids and relays, which are remotely controlled through the ENVIROMUX system. Normally-open relay switches have no current flow to the connected devices unless triggered to close and complete the circuit, which enables current flow. Based on pre-configured criteria, the ENVIROMUX system can instantly activate a number of back-up devices or security measures to prevent threats from escalating. For example, in an agricultural setting, when the ENVIROMUX system detects a drop in moisture in a monitored area of soil, the ENVIROMUX system could activate a number of hydraulic solonoid valves that are connected to the expander that would turn on a specific set of sprinklers to ensure that the affected crops receive the hydration they need. Likewise, the output relay devices connected to the expander can be powered by the ENVIROMUX-2D/5D/16D through its digital inputs or auxiliary power supply if there is room.