Project Objective
The fuel handling machine analog panel meters in the main control room of a CANDU station needed to be replaced. The legacy meters were installed during the original construction and commissioning of the plant over 30 years ago, and were beginning to fail. The legacy panel meter was no longer in production as the original manufacturer was no longer in the panel meter business.
Scope of work
The client required design and qualification of a replacement analog panel meter that would be compatible with the existing instrumentation, meet the legacy functionality and performance specifications, as well as the human factors, ElectroMagnetic Compatibility (EMC) immunity, and susceptibility requirements. Replacement meters were required for 3 different analog inputs, 4-20mADC, 0-5VDC and ±25uADC, and to replace over 50 different scales.
Kinectrics Solution
With the design constraints of having to be installed in the existing panel cutouts in the main control room panels and the desire for the replacements to resemble the legacy meters as much as possible, Kinectrics design approach was to produce an exact copy of the legacy meter.
Utilizing surplus samples of the legacy meters as our starting point, each component was re-drawn with the same dimension as the originals. Three new analog meter movements were sourced from a commercial supplier and a custom pointer arm and arrow were fabricated and installed on them. Since the the design scale bracket and scale plate were copied precisely, old scale plates from the original meters could be reused and installed in the new meters.
All plastic components were fabricated using an injection molding process and all metallic components were stamped or machined.
The replacement meters were then qualified and tested to ensure they met the required specifications.
Client Benefits
Kinectrics design provided a replacement analog meter that could be installed alongside the legacy meters and not present a human factors issue by having a different appearance. With the scale plate interchangeability, a reduced number of meters could also be stocked and remain available as required to replace any of the original 50 meters.