Re-engineering For Railway Company - Lytestyle Designs
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Re-engineering For Railway Company
Backplane.
Lytestyle Designs was tasked with providing a replacement solution to an existing wire-wrapped/PCB hybrid backplane that had become unreliable.
In the absence of wiring/schematic diagrams, the first stage was to perform a total connectivity check of all the connections and format the resulting information into a netlist.
The netlist was then read in to a schematic capture program and a circuit diagram created.
The PCB was then created in the IDE design environment using only a four layer PCB. Due regard was given to all track weights so that the track cross section match the original wiring cross sectional area.
The final product was tested for integrity against the original wire wrapped backplane using a bespoke 'shorts and opens' tester.
Speedometer.Due to failures in some of the PCBs in a speedometer unit, Lytestyle designs took on the task of reverse engineering the internal PCB. As with other tasks, there was no supplemental information such as schematic diagrams or PCB layouts. The existing PCB was fully probed for connectivity information and a schematic diagram was drawn up.
Finally all critical dimensions were recorded and used to create the outline for the PCB before components were placed and tracking completed.
A first off build of PCBs was made and tested to ensure that the re-engineered PCBs performed to the same specification as the origninals.
Finally, a production package was handed over to the customer.
Lytestyle Designs is still involved in the ongoing support of these units.
Data Entry Terminal.
When a specific version of data entry terminal went out of production, Lytestyle Designs came up with a solution to use an alternative version. The original data entry terminal had been compliant with the RS422 interface. Because this was used to communicate with other systems on the train the RS422 interface had to be preserved. Due to commercial reasons, all current versions of the data entry terminal were RS232 only. As there was a requirement for additional stock of the terminals a solution had to be found.
Lytestyle Designs created a small board 'set' that could be used to convert the RS232 interface into an RS422 interface. The existing RS232 chip in the data entry terminal was removed and a surrogate connector PCB (adap-1) was then put in place of the RS232 chip. An RS422 converter PCB (adap-2) was then plugged in to the connector PCB. Another small PCB (adap-3) was then soldered onto the external interface connector of the data entry terminal and wired to the adap-2 PCB.
As the product was identical in form, fit and function to the original data entry terminal it could still be classified as the same as the original terminal.
The above solution proved to be more cost effective than either sourcing a different data entry terminal or adding an external RS422-RS232 interface which would have had implications for user training and/or changes in maintenance procedures.
Lytestyle designs in still involved in the ongoing support of these units regarding repairs and refurbishments.
