The platform is a PLC5/40 with RSLogix. I've been given the task of installing an encoder on a piece of moving equipment (linear motion ~45 meters/140 feet) for position indication. The equipment is driven by 9 600 volt 100hp motors on 3 seperate VFDs which utilize a rack and pinion type setup. I have a shaft/gear setup that is meshed with the rack and converting linear motion into rotational motion. I intend to couple my encoder (~250 turns/cycle) to this shaft.
The equipment is approximatley 100 meters (300 feet) away from the electrical building which conatins both the PLC5 processor and all the VFDs (and several DC drives). All of the power and contol cables are run in cable tray into two junction boxes (power & control). The festoon cable is run from these JBs to the moving equipment via a typical festoon assembly - a continuos beam with cable supports on rollers that move as the equipment moves. The cable that is currently being used is Super Vutron but it is all 600 volt power and 120 volt control. There are no instruments on this piece of equipment.
I have two concerns:
1) I have decided to use a multiturn AMCI absolute encoder with a 4-20 mA output and, therefore, need to source shielded, twisted pair festoon cable.......anybody have any ideas where I will be able to find such a beast.
2) I have two of these pieces of equipment running side by side so at any given time I can have 1800 hp + another 500 hp running in close proximity plus all sorts of other equipment sharing the same tray system. Is the 4-20 mA signal my best bet. I was looking into SSI but a tech that I have a great deal of respect for told me go the 4-20 mA route. I am concerned about signal integrity due to "noise". Any ideas or suggestions?
Thanks in advance.
The equipment is approximatley 100 meters (300 feet) away from the electrical building which conatins both the PLC5 processor and all the VFDs (and several DC drives). All of the power and contol cables are run in cable tray into two junction boxes (power & control). The festoon cable is run from these JBs to the moving equipment via a typical festoon assembly - a continuos beam with cable supports on rollers that move as the equipment moves. The cable that is currently being used is Super Vutron but it is all 600 volt power and 120 volt control. There are no instruments on this piece of equipment.
I have two concerns:
1) I have decided to use a multiturn AMCI absolute encoder with a 4-20 mA output and, therefore, need to source shielded, twisted pair festoon cable.......anybody have any ideas where I will be able to find such a beast.
2) I have two of these pieces of equipment running side by side so at any given time I can have 1800 hp + another 500 hp running in close proximity plus all sorts of other equipment sharing the same tray system. Is the 4-20 mA signal my best bet. I was looking into SSI but a tech that I have a great deal of respect for told me go the 4-20 mA route. I am concerned about signal integrity due to "noise". Any ideas or suggestions?
Thanks in advance.