HI Folks, first time poster.
I am working to reserect an overgrown NU-NU (for those of you without rugrats, it is the cleanup machine on the preschool kid's show TeleTubbies.) It is a remote operated vehicle that drives around and sucks up the mud and muck off of the bottom of a concrete lined pond.
Anyway, the existing design uses a 250 foot long, 3" diameter umbilical cable that includes 2 480V motor cables, 40 to 50 control conductors, 4 optical fibers, and 2 garden hoses. The muck pump discharge is a separate 4" hose.
Umbilical management is difficult already, and now I understand that the length is about to quadruple! I believe it is time to multiplex everything over fiber and place the whole thing on a large reel.
My thought is to replace the discrete control lines and motor wiring in the umbilical with a custom cable made up of 2 optical fibers and 4 number 8 AWG conductors. I would use a PLC in the crawler to operate the hydraulic valves, monitor pressures, flows, liquid levels, and temperatures, interface to a locating system, and control a 10 HP and 15 HP motor. The crawler PLC would receive commands from another PLC in the control trailer. The trailer PLC would accept the digital and analog inputs from our standard control system, convert them to a robust communication format which would be sent over the fiber to the crawler. The trailer PLC would also convert return information back to analog and digital outputs for process monitoring.
Use a couple of VFDs in the crawler, in place of the motor starters in the control trailer, and now I am down to a power and control umbilical cable.
Am I making this more complicated than it has to be? Am I adding more failure points? I trust PLCs more than PC's, and this would reduce the number of "upgrade" relate problems. I can use industrial slip ring assemblies for the power, and if I convert the communications to light after it goes thru the slip rings, I avoid the need for optical fiber rotating unions.
Thanks for any help and/or opinions on the feasability of this.
Larry
I am working to reserect an overgrown NU-NU (for those of you without rugrats, it is the cleanup machine on the preschool kid's show TeleTubbies.) It is a remote operated vehicle that drives around and sucks up the mud and muck off of the bottom of a concrete lined pond.
Anyway, the existing design uses a 250 foot long, 3" diameter umbilical cable that includes 2 480V motor cables, 40 to 50 control conductors, 4 optical fibers, and 2 garden hoses. The muck pump discharge is a separate 4" hose.
Umbilical management is difficult already, and now I understand that the length is about to quadruple! I believe it is time to multiplex everything over fiber and place the whole thing on a large reel.
My thought is to replace the discrete control lines and motor wiring in the umbilical with a custom cable made up of 2 optical fibers and 4 number 8 AWG conductors. I would use a PLC in the crawler to operate the hydraulic valves, monitor pressures, flows, liquid levels, and temperatures, interface to a locating system, and control a 10 HP and 15 HP motor. The crawler PLC would receive commands from another PLC in the control trailer. The trailer PLC would accept the digital and analog inputs from our standard control system, convert them to a robust communication format which would be sent over the fiber to the crawler. The trailer PLC would also convert return information back to analog and digital outputs for process monitoring.
Use a couple of VFDs in the crawler, in place of the motor starters in the control trailer, and now I am down to a power and control umbilical cable.
Am I making this more complicated than it has to be? Am I adding more failure points? I trust PLCs more than PC's, and this would reduce the number of "upgrade" relate problems. I can use industrial slip ring assemblies for the power, and if I convert the communications to light after it goes thru the slip rings, I avoid the need for optical fiber rotating unions.
Thanks for any help and/or opinions on the feasability of this.
Larry