Project Design in Practice


A Challenging Environment

Denca’s UK-based customer has a facility in West Africa that processes cereals. 

They needed to upgrade the electrical controls systems for a series of conveyors that transport the cereal around the plant to different processing stations. 

Denca’s role was to provide the electrical controls design for the cabling and to design and build the Motor Control Centre panel, a PLC panel and three HMI panels (Siemens TP1200’s)

The cereal processing and conveyor transport generated large volumes of dust. By designing all systems and installations to ATEX standards, we were able to address any potential issues from this dust.

Denca’s client contracted a local partner to carry out the final installation on-site.

Although in principle, this seemed like a pretty routine project regardless of the distance between Widnes and West Africa, there were a number of specific factors which called for a very particular design solution.   

  1. Long cable runs
    The layout of the site meant that it was necessary to locate the 3 remote HMI panels up to 140m distant from the central Motor Control Panel. The specified ethernet communication protocol stipulates a maximum cable run of no more than 100m.   
  2. Local climate
    The climate on-site in West Africa meant that the control equipment would be subject to extremes of temperature. A key element of the project design was to ensure performance and reliability despite the prevailing weather conditions.
  3. ATEX certification
    On-site safety considerations meant that the project must be compliant to ATEX standards. 
  4. Short timescale
    Practical business demands dictated that the new control panels and systems needed to be designed, built, delivered installed and commissioned within 11 weeks.   

Delivering the right Design Solution

  1. Long Cable Runs
    To boost signal strength to reduce the risk of comms degradation, we incorporated Ethernet switches into the design. The HMI panels were also carefully located so that the cable lengths could be correctly and safely controlled. All cable specification fell within the parameters set by the Ethernet communication protocol.
  2. Local climate
    The MCC panel together with the PLC panel, one of the HMI panels and the Profinet Patchwork panel that enables the enhancing of the signal were placed in a specially designed, built and air conditioned Control Room located outside the main production building. However, the motors and power devices out in the field were subject to  hotter conditions. Installing appropriately sized cabling was essential. Denca conducted comprehensive cable calculations to confirm the right cable specification.
  3. ATEX certification
    As part of the ATEX led design Denca provided DSD – Descriptive System Documentation. This shows calculations providing checks that the MCC panel functions to deliver the most efficient power levels to devices. These efficiencies also avoid any unnecessary extra power supply that could cause overheating. The prevailing climate conditions also played a significant part in the ATEX calculations.
  4. Short timescale
    Denca worked to and met the very tight and strict delivery date for the system which included panel design, build of all the panels as well as having to fully function test in order for the client to be able to ship to West Africa and tie in with their other works on this project.   

Practical Project Design

Thanks to Denca’s practical, creative approach we were able to meet the client’s requirements and timescales for both the design work and for building and testing the Control Panel.

Despite the complex logistical and documentary challenges, Denca’s work meshed seamlessly with other phases of the project. As a result, all equipment was shipped to the specified schedule.

We look forward to working with our client again in the near future.

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