Controls › PLC Systems
Platforms
Platform-specific notes. Vendor names are used for identification only.
Written guides in this section
Full references, procedures, and diagnostic guides published under Platforms.
Modicon M340
Field notes on the Schneider Electric Modicon M340, a rack-based mid-range controller common in water plants: rack and CPU layout, X80 I/O, memory card behavior, Ethernet and serial communications, programming in Control Expert, and what to check on site.
8 min readUpdated Sep 5, 2026
Modicon M580
Field notes on the Schneider Electric Modicon M580, the Ethernet-backplane controller at the top of the range: remote I/O drops on a ring, hot standby CPUs, built-in security features, the networks it defines, Quantum migration, and what to check on site.
9 min readUpdated Sep 5, 2026
Control Expert
Field notes on Control Expert, the Schneider Electric engineering software for the Modicon M340 and M580: project structure, the five languages and derived function blocks, versions and files, online changes, upload information, and security settings.
8 min readUpdated Sep 5, 2026
Unity Pro
Field notes on Unity Pro, the earlier name of Control Expert and the software behind most installed Modicon M340, Quantum, and Premium applications: versions, moving projects to Control Expert, keeping an old version alive, and the Concept and PL7 originals.
7 min readUpdated Sep 5, 2026
ControlLogix
Field notes on the Rockwell Automation ControlLogix, the chassis-based controller of larger water plants: chassis and modules, tag-based memory and tasks, EtherNet/IP and older networks, controller redundancy, version matching, and what to check on site.
9 min readUpdated Sep 5, 2026
CompactLogix
Field notes on the Rockwell Automation CompactLogix, the smaller Logix controller behind most lift stations and small plants: families and I/O, the two Ethernet ports, what it shares with ControlLogix and what it lacks, and what to check on site.
8 min readUpdated Sep 5, 2026
Topics in this area
Schneider Electric
Schneider Electric in industrial control systems — Platforms, covering 4 topic areas in the CurryControls.com controls and automation knowledge hub.
4 topics
Rockwell Automation
Rockwell Automation in industrial control systems — Platforms, covering 3 topic areas in the CurryControls.com controls and automation knowledge hub.
3 topics
Siemens
Siemens — practical reference notes for controls engineers, integrators, and technicians working with platforms.
AutomationDirect
AutomationDirect — practical reference notes for controls engineers, integrators, and technicians working with platforms.
Legacy Systems
Keeping older controllers running and planning a migration.
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References to manufacturers, products, model numbers, software platforms, technical specifications, companies, standards organizations, or other organizations are provided for informational purposes and do not imply sponsorship, endorsement, authorization, or affiliation unless expressly stated. Manufacturer specifications must be independently verified against current manufacturer documentation.