After more than 10 years with next to nothing published here, a quick note: PascalSCADA is alive. Not just alive — the last few weeks have seen more work go into the project than any recent stretch, so a summary is in order.
Two new protocol drivers
- S7CommPlus — the native protocol TIA Portal uses to talk to S7-1200 and S7-1500 PLCs. Unlike the existing ISOTCP driver, S7CommPlus does not require turning off optimized block access: you address the tag by its symbolic name (
DB4.Var1,MArea.Clock_10Hz), the same way TIA does. It supports username/password for CPUs with access protection. - EtherNet/IP (CIP) — a new driver for Rockwell/Allen-Bradley Logix-family PLCs (ControlLogix, CompactLogix…), also with symbolic addressing by tag name. It ships with its own Tag Builder wizard.
A big cleanup, backed by real tests
This is the less flashy but more important part: PascalSCADA never had a real automated test suite. That changed. Practically the whole library — communication ports, the protocol drivers (Modbus RTU/TCP, Melsec, S7/ISOTCP, S7CommPlus, EtherNet/IP, West ASCII, i-Box), the tag layer and the HMI control library — got unit tests, and chasing every test uncovered a pile of defects that had been sitting in the code, some for years:
- Modbus reads that left the port locked;
- the ISOTCP driver waiting forever for a PLC that never answered;
- West ASCII writes that lost the value’s magnitude;
- memory leaks in central places — the scan thread, the event and alarm loggers, the central user manager, the network mutex server;
- the on-screen keyboard on Windows, where the numeric keypad’s
-and.came out as a letter or garbage; - a
THMICheckBoxthat sometimes wrote to its tag twice for a single change; - the security flag that, in one specific case, disabled every control created at run time.
The real list is much longer — it’s all in the commit history of the GitHub repository.
Building and testing on five platforms
The project now has continuous integration running the tests on Windows 32/64, Linux 32/64 and FreeBSD 64 on every change — plus tests on ARM (ARMHF/AARCH64). That already caught subtle differences between platforms that would have gone unnoticed before (a TCriticalSection signaling differently across systems, Unix-specific serial device paths, among others).
The documentation got a pass too
The site had several “under construction” pages that had been sitting untouched forever, and others that were badly out of date. Most of it was rewritten: Tags, S7 Protocol over ISOTCP, Mitsubishi Melsec TCP, HMI Control Library, Security system, Scale processors, HMIDBConnection, the protocol drivers overview, and a new tutorial, Writing a protocol driver, for anyone who wants to add support for another device. The installation page was also brought up to date for the current workflow (GitHub + current Lazarus, no more ZeosLib).
Right now, installing all of this means getting the code straight from GitHub (see How to install) — the package published on Lazarus’ Online Package Manager is still version 0.7.7, from 2021. That should change in the coming weeks: the plan is to publish a new OPM release with both new drivers and all of this cleanup, for anyone who’d rather install straight from the IDE without cloning a repository.
If you use PascalSCADA, ran into something broken, or have a suggestion, open an issue on GitHub — that’s where the project moved to, and that’s where the conversation happens now.