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Our Top Tips

As part of our commitment to help build a better industry, we are going to be sharing a series of best-practices and key tips from within the global team. In the first of the series, I managed to grab some time with our Design Manager Barry Ward to get his thoughts on writing BeMS Software and what he believe's to be the key points to consider. Software is a vital part of any BeMS or BMS control system. Here is a summary of his views;

 

  • Read and fully understand the specifications and schematics and always make sure you are working to the latest drawings and schedules.
  • To reduce the possibility of missing items when designing the control strategy it is a good idea to generate documentation such as drawings or I/O schedules first. 
  • Always try to break the plant down into manageable chunks;
    • Primary Plant (Boilers, Chillers etc).
    • Secondary Plant (Pumps, Heat Exchangers etc).
    • Air Plant (AHU's, Fans etc).
    • Domestic Hot Water Systems.
  • Always place importance on safety interlocks such as fire alarms and pressurisation unit alarms; these will be common to multiple systems and should also be hard wired to the control unit. Remember, safety interlocks take priority over normal control and should be used in software just before the outputs.
  • Keep safety interlocks just before the drivers so that other software can not bypass the safety feature.
  • Where possible group your sensors, digital inputs and user adjustable points together and on the first pages of the software.
  • As well as labels on physical inputs and outputs; it is also good practice to give logic and function modules descriptive labels. This is also useful if you use to/from connectives in multiple locations within your software.
  • Disconnect the I/O from a controller prior to installing the software, this will ensure the plant does not start unexpectedly.
  • Check the software using a simulation mode this saves time on site.
  • Confirm the ranges of analogue I/O such as sensors/actuators match the ranges set up in the software.
  • Make sure alarm settings have sensible values to prevent nuisance alarms.
  • Be careful with controller attibutes - especially if using for IC Comms.
  • Ensure software knobs have sensible upper and lower limits.
  • ALWAYS use occupation times, setpoints etc supplied by client/ end user.
  • Carry out Loop tuning ensuring the inner loop (closest to the driver) is tuned first.
  • Keep records of commissioined values.
  • Download and upload after software alterations to synchronise. ALWAYS archive backup files in 2 different locations.

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If you would like more information or to discuss in person please contact Barry for a chat on 01795 411534.

Written by global associates on 30th January 2018