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- Hardware Tools
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- PLCs – Programmable Logic Controllers
- PROFIBUS
- Protocol Converters & Gateways
- RealTime Ethernet
- S5 Retrofit
- Hitex UK Products
- In-circuit Emulation
- Linux Development for ARM
- Software Quality
- Development Tools Supported Microcontrollers
PLCs – Programmable Logic Controllers
PLCs are specialised digital computers optimised for hard-real-time control applications and used in process control and factory automation.
In a typical application a central PLC running a control algorithm connects to distributed Analogue and Digital I/O Modules, Motor Controls, Sensors, Instrumentation etc. via a Fieldbus network.
Although there are many types of PLC from many different manufacturers, PLC programming languages have been rationalised under a single IEC standard.
IEC 61131-3 currently defines five programming languages for programmable control systems: FBD (Function Block Diagram), LD (Ladder Diagram), ST (Structured Text, similar to the Pascal programming language), IL (Instruction List, similar to assembly language) and SFC (Sequential Function Chart). These techniques emphasise logical organisation of operations.
Hitex and partners offer a wide range of PLCs and associated products such as Remote I/O units, PLC Connectivity Solutions, OPC Servers, Fieldbus Interfaces, Fieldbus Diagnostics, and Network Configuration and Management Tools.
Until recently, a PLC (Programmable logic controller) would communicate with a slave machine using one of several possible open or proprietary protocols, such as Modbus, Sinec H1, Profibus, CANopen, DeviceNet or FOUNDATION Fieldbus. However, interest has increased in the use of Ethernet as the link-layer protocol, with one of the above protocols as the application-layer.
Some of the advantages are:
- Increased speed, up from 9.6 kbit/s with RS-232 to 1 Gbit/s with Gigabit Ethernet over Cat5e/Cat6 cables or optical fiber
- Increased distance
- Ability to use standard access points, routers, switches, hubs, cables and optical fiber, which are immensely cheaper than the equivalent serial-port devices
- Ability to have more than two nodes on link, which was possible with RS-485 but not with RS-232
- Peer-to-peer architectures may replace master-slave ones
- Better interoperability
Hitex UK has tools for analysing the hardware and software layers of your ethernet network.