SoftPLC process stations

The SoftPLC family contains both the MiniPLC controllers (PLCs), and industrial PC-based process stations for projects requiring more resources.


MiniPLC is a platform with embedded real time operating system, containing SoftPLC runtime, compiled application, and other services like web server, Modbus serial server etc. The devices are powered by 12…30 V DC, or 12…24 V AC. They contain 1 or 3 serial ports and an Ethernet interface, a configurable LCD display and 6 pushbuttons. Currently supported types are IPLC201, IPLC301, IPLC500, IPLC501 and their modifications (with no LCD display). A compact PLC (with integrated inputs and outputs) offering excellent price / performance ratio is a MXPLC.

IPLC301 – connector layout

MiniPLC is delivered in two ranges which offer different computing power: the basic range with a BECK OS (IPLC201, IPLC301), and a more powerful platform using Linux (IPLC500, IPLC510).

Note: The process stations IPLC500IPLC510 and MXPLC-L (with OS Linux) do NOT have the web server.

MiniPLCs communicate with the I/O modules over serial interfaces:

IPLC201(500)  1×RS485 (COM4)

IPLC301(510)   2×RS232 (COM1,2), 2×RS485 (COM3, 4)

The RS485 interface can be connected directly to the I/O bus. The interface is galvanically separated and terminated by a connector with removable screw terminals marked  K+ and K-. There are 2 LEDs for each RS485:

TX (red) – transmitting data
RX (green) – receiving data

When communicating properly, both LEDs are flashing fast in turns with no larger breaks.

The RS232 interfaces are mostly used for metering readouts over M-Bus converters (R095R096) or for GSM modem to send alarm SMS. If the PLC is installed in the panel door, use  RS232L, a L-piece to connect the CANNON9 cable comfortably..

The Ethernet interface is used for links to the management level (SCADA, web, OPC server etc.) and for configuration and program upload. The communication follows over  Platform configurator, which is part of the SoftPLC IDE, the engineering software. For communication there is only an Ethernet cross cable necessary, or the MiniPLC must be connected in a local LAN. No other converters / communication cards / cables are necessary. The computer (notebook), which hosts the IDE, must have an Ethernet card.

The MiniPLC is installed

  • in a panel on a DIN rail, so that the LCD display and buttons are accessible only after the panel door is open, or
  • in an aperture sized 107 x 47 mm in the panel door using a metal frame (type ID FRAME) and a piece of DIN rail (150 mm length), then the display and buttons are accessible from outside of the panel.

PC-based process stations

These are  typically embedded PCs with 8“ touch screen and Windows 7 Embedded, which host the application software runtime. Their processing power is substantially higher than that of the MiniPLC. The touch screen works as a HMI which may control also other (Mini)PLCs in the network.

IPCT.1 uses power of 12 DC / 2 A or 230 V AC with a switched power supply which is part of delivery. Exceptions see below.


The SoftPLC Runtime may run on any PC with OS Windows XP / XP Embedded / 7 / 8 / 10; this is used when the SoftPLC is utilized as a protocol converter: the SoftPLC Runtime is installed at the management station, collecting data from 3rdparty systems e.g. over BACnet and acts as an OPC server for SCADA integration..

The most used one is the IPCT.1, a process station with a 8“ LCD touch screen. It contains following interfaces:

2x        Ethernet
2x        RS232 (COM1, COM2)
4x        USB

For applications where HMI is not required the IPCB.1can be used, which has 4 serial ports. IPCB.1 is suitable e.g. as a data concentrator for more M-Bus lines.

IPCT.1 is installed into panel door or any other suitable box. Make sure that there is sufficient air circulation for cooling, especially around the back part and sides of the unit.  In most cases, apertures in the panel with no forced air circulation are enough. When installing into watertight plastic boxes, air circulation holes in the upper and lower part of the box are necessary.

The front panel aperture shall be of 222 x 167 mm, panel thickness 10 mm maximum. Part of delivery are six metal clamps which fix the process station from the inner side of the panel door.

The process stations are powered either from

  • attached switching power supply 230 V AC / 12 V DC, or from
  • a stabilised power supply of 11 … 28 V DC in the panel providing at least 35 VA extra power.

Remember to install a 230 V / 6 A power socket in the panel for the power adapter.

As the IPCT.1 is equipped by RS232 ports, to connect to a bus with the I/O modules, a RS232 / RS485 converter is necessary, e.g. domat R012. The converter also provides galvanic separation between the RS485 (I/O bus) and COM ports of IPCT.1.

The converter has two screw terminals to connect the RS485 bus: K+K-. Close to the connector are two BUS END switches used to terminate the bus.

The converter is powered through terminals G and G0 by 10..35 V DC, or 12…24 V AC. If the converter is located in a separate box together with the process station (at the managers’ office, in a reception etc.), and the I/O modules are in a remote epanel close to the controlled technology, the converter may be powered from the same power source as the IPCT.1. If the converter is in the panel together with I/O modules, it is powered from the same transformer or power supply as the I/O modules.

The converter is connected to the process station using a zero modem cable, terminated by 2x CANNON9 F connectors. (Connection of pins 2, 3, and 5 is enough.) The cable is supplied on request free of charge together with the R012.

Converter R012

The baudrate is set by DIP switches, accessible after the upper cover is removed. The default communication speed is 9600 bps, 8 bit, which is also the default for the Domat I/O modules.

Other devices, like GSM modems for sending and receiving of SMS messages, are connected using cables which are part of delivery of these devices. If connecting 3rdparty devices, make sure that the communication bus is protected from other voltage.

If a GSM modem or router is part of the installation, remember to install a 230 V power socket for the power adapter supply, and enough space in the panel, especially in the installation boxes with IPCT.1 where there is usually not much space left.

Operating system: There is a CF card in the process station, containing an image of Windows 7 Embedded and a second disk used as data storage space for SoftPLC projects.

During normal operation the Touchscreen application occupies the entire display area, and the OS icons are not visible. The operating system is not accesssible using just the touch screen. It is possible to shut down the Touch screen application using a service code and operate the system. The service code is set up in the commissioning phase by the software engineer who installs the device.

The runtime (process control logic) and HMI are run automatically after the operating system boots up.