While there was the option of producing a wiring harness which would allow the respective control terminals to be connected, it was decided that to give the complete assurance a connection error could not be made during initial installation and commissioning (or when a power supply was replaced) then a 'Pass Through' PCB would be designed and manufactured. Effectively hard-wiring the control connections together.
The pin-outs of the connectors on each power supply were reviewed using the manufacturers’ datasheets and manuals. The logic differences and voltage levels were determined from information provided by the customer combined with the limited information contained in the product documentation. The differences were overcome using a current limited open collector circuit (providing protection in the event of a miss-connection) and a latching relay to accommodate the difference between the Hi/Lo signal for On and Off on one power supply and the separate On and Off signals on the other. The simplicity of the circuit design and the low number of components reduced the risk of component failure. The dimensions of the board were derived from a mechanical outline drawing from the manual of one of the power supplies with the board having standoffs to ensure it would not clash with any feature on the rear panel. These dimensions were imported to Altium Design, where the schematic was also drawn up and the PCB was rapidly designed. The Gerber files were then sent to one of our PCB manufacturing partners on a quick turn-around and supplied back to our electronics production facility for final assembly and test.
The finished pass-through PCB’s were supplied and have allowed the customer to save a significant amount of money by removing the need to entirely replace the old power supplies while ensuring an error free and reliable interconnect solution.
This is an example of how May & Scofield's capabilities to design and manufacture high reliability, product interconnections, could be utilized by other customers in a different application or industry.