PRM Extension Modules from akYtec


Prior to the appearance of the PRM Extension Module, our Programmable Relay PR200 was a compact small controller with a total of 22 inputs and outputs. In most cases it is good to have a compact device, but performance and flexibility often play an important role as well. Modularity is the key to meeting the growing demands of your control system. With the PRM Extension Modules, the PR200 mini controller is no longer a compact PLC. Now it's a modular expandable device with up to 54 I/O points.

Compact mini PLC and I/O Extension Modules

Inputs & Outputs

The PRM module is equipped with 8 digital inputs and 8 digital outputs.

The inputs process signals from sensors with switch contact output or PNP open-collector transistor outputs.

The outputs serve as normally open relays and can be connected in series with a control or indicator device. They are rated for up to 5 A, 250 V AC and up to 3 A, 30 V DC, regardless of the input voltage.

If communication with the PR200 has been interrupted, the outputs of the PRM module take values previously defined by the user. This function is called output safe state.

Internal bus and easy configuration

The modules are connected to the compact mini PLC PR200 (hereinafter ‘base device’) via an internal bus. This bus is implemented as an SPI interface and a short flexible flat cable consisting of 10 wires.

The internal bus provides a fast and easy-to-configure connection of the PRM modules to the base device. It only takes a few clicks to add a PRM module to your project in akYtec ALP, the software for programming the base device. Unlike any Modbus-based extension module, a PRM module eliminates the need to deal with Modbus registers and functions. Once a PRM module has been added to the project, its inputs and outputs are available for direct linking to the variables and function blocks in your project.

Power supply and galvanic isolation

The requirements of the supply voltage of a PRM Extension Module differ depending on the device variant. It can be either 24 V DC or 230 V AC. With the 24 V device, a debounce filter can be set in the range of 0 ... 255 ms at its inputs.

Thanks to its own voltage terminals, each PRM unit can be powered by a separate power supply. As a result, the base unit and the PRM Extension Module can cooperate with different supply voltages.

The power supply, input and output terminals are galvanically isolated from the internal circuits with isolation voltage up to 2830 V, ensuring additional device reliability and user safety.


The device has a compact enclosure that can be easily snapped onto a 35 mm standard DIN-rail without the need for any tools. Due to its design and depth, each PRM module can be mounted not only in a control cabinet but also in a distribution board.

Each input and output of the device has an LED to indicate its status. The power and error indicator is also available on the front panel of the device.

The PRM expansion modules feature removable I/O terminal blocks for quick and easy device replacement.

The above-described Extension Modules can be selected and ordered here.