PC-10Control systems · PLC
PLC, HMI & SCADA Systems
Controllers, I/O, operator interfaces and supervisory software, selected as one architecture. Hardware follows the I/O count, the process, the network — and the people who will maintain it.
01Scope
What's included
Controllers, I/O, operator panels and supervisory software.
- ControllersCompact, modular and redundant PLCs.
- Remote and distributed I/OI/O stations near the field on an industrial network, including HART-capable analog modules.
- Operator panels (HMI)Local graphic panels for machines, skids and process units.
- SCADA and historiansSupervisory software, alarm management, trends, reports and data historians.
- Industrial networkingManaged switches, gateways and protocol converters between devices, controllers and IT systems.
- Control panelsControl, marshalling and remote I/O panels with power distribution.
02Compare
Architecture options
The architecture is chosen for the process and its availability requirement, not for the controller — see the PLC vs DCS guide for the larger decision.
| Principle | How it works | Suited for | Considerations |
|---|---|---|---|
| Compact PLC | How it worksA controller with integrated or lightly expandable I/O in one unit. | Suited forMachines, skids, pump stations and small utility systems. | ConsiderationsLimited I/O, memory and communication ports — plan expansion headroom from the start. |
| Modular PLC with remote I/O | How it worksA rack-based controller with I/O stations distributed near the field over an industrial network. | Suited forProcess units, plant utilities and larger machine lines; reduces field wiring. | ConsiderationsNetwork design and diagnostics become part of the system, along with firmware and spares management. |
| Redundant controllers | How it worksHot-standby CPUs with redundant power and networks, so one failure does not stop control. | Suited forContinuous processes where downtime is costly — utilities, water treatment, critical units. | ConsiderationsRedundancy must extend to power, networks and critical I/O to be meaningful; higher engineering effort. |
| DCS | How it worksAn integrated system with one database, engineering environment and operator stations across the plant. | Suited forLarge continuous processes with many analog loops and close operator interaction. | ConsiderationsHigher entry cost; best value on large, integrated plants. |
| HMI operator panel | How it worksA local graphic display for operation, alarms and maintenance at the equipment. | Suited forMachines, skids and local control stations. | ConsiderationsFront-panel ingress rating, screen size, and a tag and alarm philosophy shared with SCADA. |
| SCADA | How it worksSupervisory software that collects data from controllers across a site or several sites, with alarms, trends and reports. | Suited forPlant-wide supervision, water networks, utilities and multi-site monitoring. | ConsiderationsLicensing by tags and clients, server redundancy, historian sizing and cybersecurity (IEC 62443). |
General engineering guidance. Limits and performance depend on the specific instrument and variant — confirm them against the manufacturer's datasheet for the selected model.
03Specify
What to specify
The parameters that decide the selection. State each with its unit; where a value is not known yet, say so — it becomes part of the engineering review.
I/O count and types
Digital, analog, temperature and HART I/O — with spare capacity for expansion and changes.
Control task
Sequential, PID, batch or motion control decide controller class and software.
Availability
Whether controller, power, network or server redundancy is needed.
Existing platform
Plant standards, installed spares and maintenance skills — often decisive in brownfield sites.
Field communication
The protocols the existing instruments, drives and analyzers speak.
Operator interface
Number of stations, local and central operation, remote or web clients.
Data and reporting
Historian, reports and, where applicable, electronic-record and data-integrity requirements — for example 21 CFR Part 11 or EU GMP Annex 11 for plants supplying those markets.
Cybersecurity and remote access
Network segmentation, user management and controlled remote support.
Interfaces to safety systems
Safety instrumented functions are normally engineered independently of the basic control system (IEC 61511) — state which signals the control system must exchange with them.
Environment and lifecycle
Panel location, temperature and ingress; product lifecycle status, spares availability and documentation.
04Integrate
Outputs & communication
Interfaces typically offered in this category, and what each means for the control system. Availability depends on the specific model.
- 4–20 mAAnalog
- Current loop with a live zero: 4 mA is the bottom of the range, so a broken wire (0 mA) is distinguishable from a zero reading. Two-wire (loop-powered) on most transmitters; four-wire with an active output on line-powered instruments such as analyzers — the I/O channel must match. Accepted by practically every PLC and DCS analog input.
- HARTDigital over analog
- A digital signal (Bell 202 FSK, 1200/2200 Hz) superimposed on the 4–20 mA loop — configuration, diagnostics and secondary variables over the existing two wires.
- Modbus RTUSerial
- Serial client/server (formerly master/slave) protocol, typically over RS-485: several devices share one multi-drop cable and the client polls each for its values — common on analyzers, multivariable meters and packaged equipment.
- PROFIBUS DPFieldbus
- RS-485 fieldbus for remote I/O, drives and controllers; the backbone that PROFIBUS PA segments couple into.
- Industrial EthernetNetwork
- PROFINET, EtherNet/IP or Modbus TCP — the networks that connect controllers, remote I/O, drives and HMIs, and increasingly carry device data from the field as well.
- OPC UANetwork
- Vendor-neutral, secure data exchange between controllers, SCADA, historians and higher-level software — the usual bridge between control and information systems.
- Relay / discreteDiscrete
- Switched contact or transistor output for alarms, interlocks and pump or valve control — it carries a state, not a value.
05Install
Installation practice
- Segregate power, signal and communication cabling, and keep intrinsically safe circuits separate inside panels.
- Leave spare I/O and panel space, and document tag names, addresses and network topology as built.
- Design the network deliberately: segmentation between control and office networks, managed switches and controlled remote access.
- For brownfield replacements, audit existing logic, I/O and interfaces first, and plan cut-over and testing (FAT and SAT) before any change on site.
06Products
PLC, HMI & SCADA products
Status · no models listed
Specific models are not listed on the site.
Our engineers can recommend a controller, HMI and SCADA architecture against your requirements. The selection checklist on this page is the information that decides it — send what you have.
How a review runs
PLC01Share the system data
I/O count, the process, existing controllers and network, and who maintains it.
02Engineering review
The architecture, I/O and communication are checked against the application.
03System options
Suitable controllers, HMI and SCADA options are proposed with the data needed to confirm the selection.
Next steps
Where to go next
- 01SolutionIndustrial AutomationPLC, HMI, SCADA and DCS engineering for process and machine control, from control panels to plant-wide supervision.
- 02ResourcePLC–SCADA Integration ArchitectureLayers, protocols, tag design and network considerations for a maintainable system.
- 03Related categoryControl Valves & ActuatorsControl and on/off valves, actuators and positioners.
Engineering enquiry
Planning a control-system architecture?
Share the I/O count, the process, the existing controllers and network, and who will maintain it. Our engineers can help define the controller, HMI and SCADA architecture.