Codesys on Sagatowski GmbH

CODESYS is not open-source

Tue, 16 Dec 2025 00:00:00 +0000

From time to time I see posts and comments on the web saying that CODESYS is open-source. Normally I ignore making corrections, but last week something weird happened. We were involved in a bidding for a contract, where the buyer selected an integrator which of one of the selection criteria for the other system was that they used the open-source IDE/runtime CODESYS. It didn’t say open. It said open-source.

OSCAT basic library in TwinCAT

Mon, 01 Jan 2018 00:00:00 +0000

If you’ve done development in TwinCAT for some time, you’ve most likely come across at least one of the OSCAT libraries. These are open source libraries developed in accordance to the IEC61131-3 standard. They provide a total of three different libraries; OSCAT-Basic, OSCAT-Building and OSCAT-Network. I’ve so far only used the OSCAT-Basic library, which provides function blocks and functions for engineering, mathematics, string handling, time/date and much more. There is only a small problem with using the OSCAT-Basic library in TwinCAT – there is a broken reference in it! What follows is a guide on how you can fix this so that you can fully utilize this library in TwinCAT.

61131-3 PLC on the cheap

Sun, 06 Nov 2016 00:00:00 +0000

3S-Smart Software Solutions has since pretty long had a Raspberry Pi (RPI) target image available for their CODESYS runtime. The intention was to create something that you could buy very cheap, primarily for students and such to learn how to program 61131-3.

As I’m primarily working with TwinCAT 3, which is based on CODESYS, I’ve been thinking about building a really cheap 61131-3 compatible PLC based on the RPI and the CODESYS target. I didn’t just want it to be one board laying around in my home, but I also wanted it to have the “industrial” feeling, and luckily I found a perfect development board + case for me to initialize the project. Now that it’s finished, I have a PLC running an EtherCAT master in the CODESYS runtime for almost no money at all.