PLC Programming / SCADA
Our knowledge has also enabled us to propose PLC/HMI based systems to our clients to replace existing bespoke hard-wired systems, with standard ‘off the shelf’ PLC solutions, reducing wiring time but also allowing more flexibility within the new system, such as language options, data logging, password protection etc…
Site surveys and Feasibility studies can be offered at the scoping stage of any potential projects and then once the control philosophy has been finalised a full Functional Design Specification is produced for the system, detailing all PLC/HMI hardware and software operations.
Over the years our in house Software Design Team have gained extensive experience using different communication protocols, Intelligent Networks and Radio Systems. This gives us the ability to offer different solutions to the client dependent on existing network limitation, distance issues or specified site communication protocols.
These include but are not limited to:
- Ethernet I/P
- Profibus
- Modbus
- Fibre-Optic
- PSTN/PSDN
- Radio Links
Testing and Commissioning forms a vital part of the software process and this is available on all projects that have a PLC/HMI involvement. Detailed software Test documents are produced in conjunction with the FDS to allow both our engineers and the client to work through the process area by area and test the functionality of the software.
This can either be carried out on the bench at our works or on site.
These can also be developed for Commissioning and Site Acceptance Test Documents.
On certain projects we have developed process simulation software within the main PLC programme to simulate site activities (for instance a Sand Filter Backwashing Process). This simulates the Analogue and Digital I/O connections without actually having these connected to the system.
This involves the development of specialised Function Blocks to simulate the reactions of all external plant equipment. For example a valve actuator has open and closed output commands and the block will simulate the open and closed limits operating after a preset amount of time has elapsed.
Modelling of analogue levels is based on expected conditions of the plant. For example if we start a pump we expect a flow from it to cause an increase in level to the tank it is feeding over a period of time.
By applying these techniques we are able to simulate the operation of both simple and complex processes.
