A company specializing in lock-out tag-out equipment for use in nuclear power plants developed a product that required electronics to count the rotation and direction of a slow-moving motorized shaft. The system needed to be highly reliable, provide a timestamp of each complete rotation, and have a battery life of five years on a single nickel-metal hydride (NiMH) battery the size of 1/3 of an AA. An LCD shows the number of revolutions, and plant operators can download logs to a PC via USB.
Henway was called in because the company wanted to expand the use of this technology into other products. To achieve this, a few modifications to the original electronics were required, but they didn’t have all the files, and they lost communication with the original designer, leaving them feeling stuck.
They called Henway to review their files, and we quickly discovered discrepancies.
- The bill of materials (BOM) didn’t match the PDF schematic or the parts on the PCB.
- The PCB engineering files were just the .prj file. No .sch or .pcb files.
- There were several source code hex files, but nobody from the company knew which version was correct.
- There was source code but no documentation to accompany it.
After delivering the news, we explained our plan and the cost to get them back on track. The heavy weight of the situation felt lighter to the customer, and they were cheered up after hearing this:
First, Henway would document the project requirements, create a block diagram, and a hardware and software spec. This is the foundation where we can perform a gap analysis between their engineering files and how the product needs to work. We created a list of discrepancies and ranked them in order of importance.
Our hardware team was then assigned to recreate the schematic and PCB layout files using the customer’s STEP files as a reference to place the critical components in the right spot and replicate the board outline exactly. Henway built the new PCB prototypes in-house. While the PCBs were being assembled, the software/firmware engineers created specialty block-testing firmware to validate the new hardware design. Then they combed through the source code, fixed bugs, and upgraded the code comments for future development.
In the end, the customer received a clean PCB design and manufacturing package along with validated prototype samples. Currently, Henway is working with this customer on a production run of the fixed design and aiding in the specs for their next project, which utilizes the same technology but for multiple spinning shafts!