Gemo AR2-A-230VAC-8D-RTC – Compact Smart Relay / PLC with 8 Digital Inputs, Relay Outputs and Real-Time Clock

Gemo AR2-A-230VAC-8D-RTC is a compact smart relay / PLC designed for machine control, panel automation, sequencing, timing and calendar-based applications. It operates directly from an AC mains supply and provides 8 digital inputs, 5 relay outputs, a dedicated PTC temperature-sensor input and a battery-backed real-time clock.

Gemo AR2 controllers have been available through our website since 2011.

Power supply and I/O

Power supply: 100–240 VAC, 50/60 Hz. Although the model designation includes 230VAC, the controller is designed for a wide AC mains input range.

Digital inputs: 8 low-voltage DC digital inputs are provided. The controller itself is AC-powered, but the digital-input terminals are not intended for 230 VAC signals.

Auxiliary DC supply: The AC-powered AR2-A-8D series provides an internal 18 VDC auxiliary supply for use with its digital-input circuitry.

Digital input filter: Standard input filtering is at least 8 ms for ON-to-OFF and OFF-to-ON transitions.

Relay outputs: 5 digital relay outputs, rated up to 250 VAC / 2 A for resistive loads. Suitable suppression or interface components should be considered when switching inductive loads such as contactor coils and solenoid valves.

Analog input: This model has no general-purpose analog input.

Analog output: Not available.

PTC temperature input: One dedicated input is provided for a PTC temperature sensor, allowing temperature information to be used directly in the control program.

Battery-backed real-time clock

The AR2-A-230VAC-8D-RTC includes a battery-backed real-time clock. This allows control functions to operate according to actual date and time rather than only elapsed timer values.

Weekly and annual schedules can be created for applications such as pumps, ventilation systems, lighting, heating equipment and machinery that must operate at predefined times.

For applications that do not require calendar-based scheduling, see the Gemo AR2-A-230VAC-8D version without RTC.

Ladder programming and internal functions

The AR2-A-8D series is programmed with GEMO Ladder Editor. The ladder workspace provides 256 program lines, 5 contact columns and 1 output column. Rising-edge and falling-edge functions can be assigned to contacts where required.

Programs are transferred through the controller's RS-232 programming interface.

Internal logic resources include 32 timers, 32 16-bit up/down counters, 32 offset counter comparators, fast-counter functions and internal auxiliary relays.

Ladder scan time: Approximately 10 ms or less, depending on the application program.

Timers and RTC: Standard timers are used for elapsed-time functions within the ladder program, while the RTC is used for actual date- and time-based scheduling. These are separate functions and should not be confused.

Servo and step motor control

The relay-output AR2-A-230VAC-8D-RTC does not provide a high-speed pulse / direction output for positioning servo or step motor systems.

Applications requiring pulse-train positioning should use a PLC or motion controller designed specifically for high-speed motion control.

PID control

A built-in PID control algorithm is not provided. Closed-loop temperature or process-control applications should use a suitable process controller or a PLC with integrated PID functionality.

Display and operator functions

The controller features a 2 × 16 character backlit LCD display and three programmable front-panel function keys. Machine status, timer values, counter values, RTC information and operator messages can be displayed directly on the unit.

Can an external HMI be connected? The AR2-A-8D series is not intended for the external Modbus gateway / HMI arrangement used with larger AR2 models. If an external operator panel or Modbus RTU connection is required, a suitable higher-level AR2 model or another PLC / HMI platform should be selected.

I/O expansion: This model is not expandable. If an application requires more than 8 inputs or 5 outputs, an expandable AR2 model should be selected instead.

Operating environment

Operating temperature: 0 to 50 °C.

Protection rating: IP20 according to EN 60529.

Relative humidity: Up to 80% at 30 °C, decreasing as temperature rises to approximately 50% at 50 °C, non-condensing.

Installation altitude: Below approximately 2000 m above sea level.

Terminal tightening torque: Maximum 0.5 N·m.

EMC and panel layout: When the controller is installed in the same enclosure as AC motor drives, frequency inverters, contactors or other sources of electrical noise, control wiring should be separated from power wiring wherever practical. Proper grounding and shielding practices should also be applied.

Because this controller is powered directly from the AC mains, correct isolation, overcurrent protection and physical separation between mains wiring and low-voltage control wiring are particularly important.

Gemo AR2 programming software and documentation

Download GEMO Ladder Editor V2.4 programming software for AR2 programming and configuration.

For programming instructions, timer and counter functions and RTC configuration, refer to the Gemo AR2 PLC English user manual.

For additional Gemo models and pricing, visit the Gemo price list, Gemo Electronic main page or our PLC product group.

For technical information and product selection, use our Gemo contact page or contact us at gemo@otomasyonavm.com.

Installation notice: Installation, wiring and commissioning of the Gemo AR2 should be carried out only by qualified technical personnel. Disconnect the AC supply before wiring or servicing the controller. Suitable isolation and overcurrent protection should be provided, and mains and low-voltage control wiring should be installed in accordance with the manufacturer's instructions and applicable electrical-safety requirements.