Updated: Feb 8, 2021
I was recently asked if it was cheaper to go with multiplexed electrical or to go with regular dash switches? It is a question that pops up frequently so I thought I would share with everyone.
All Spartan chassis come standard with multiplexed wiring. Metalfab has also standardized on multiplexed wiring. The reason being that due to the number of interlocks required in today's fire trucks both to meet NFPA/ULC and customer requirements, going with multiplexed wiring is more reliable as we can do the interlocks through programing. Using standard wiring practices, we would need to use relays, diodes, etc. which add complexity to the wiring system and also more areas where the possibility of failure is present.
That being said, using a multiplexed wiring system you can either use the standard rocker type switches or you can go with a VISTA screen to look after the switching of the elements on the truck (lights, etc.) The Spartan FC-94 is standard multiplexed with rocker switches. We could add the VISTA screen after the fact at an additional cost. The Spartan Metro Star and Gladiator come standard with the VISTA screen and they also have rocker switches as an option. On a commercial chassis, our standard is rocker switches but we could do a VISTA screen at an additional cost as well.
Metalfab's standard multiplex system is Weldon V-Mux. We use V-Mux on all chassis except for International commercial chassis. On International chassis, we use International's multiplex system - Diamond Logic. This system is nice as we can program the system to include our electrical here at our plant. After we are finished, prior to delivery, we upload the electrical program to the International servers. What that means for the end user is that wherever you are located and to whichever International service center you take your truck, they can access the entire electrical file for that truck. In terms of the VMUX system, we keep the files archived here at our plant and can send to you as required.
It is a fairly quick and to the point response but It sums up the options available. If you have any questions or if you would like to discuss, please feel free to contact me at anytime.