Need help selecting I/O medium. (wired, wireless, inductive coupling)

[stayclashy80]

Not sure how to word the title but here's my scenario. We have a carriage that moves at high speed with an energy chain and the cable bends in a small radius. We are having issues with the cable failing every 3 months. We have tried many different types of high flex cables and none have worked so far. Currently using a 113302 - LÜTZE SUPERFLEX® PLUS type cable. My thought is to go away from physical cable and do wireless or inductive coupling. The application is just 2 reed switch inputs on a pneumatic actuator. I have used Banner and phoenix wireless in the past but nothing that moved this fast. I am also intrigued by inductive coupling but not sure how the signal would be transmitted with the 2 sides moving. Any advice would be appreciated. Very new to this site so I will apologize now if this is not a topic discussed here. Thanks

 

[mk42]

How fast do you need to be able to read the IO?

 

[JesperMP]

If you go wireless or inductive coupling, how do you supply power to the sensors ?

 

[stayclashy80]

Hmm. I looked at my scan time for this plc and its at 20msec however I looked at ServiceLab for siemens and it shows the signal takes 350msec to change states. Unfortunately Siemens and ServiceLab is new to me so I'm not sure if the 350msec is just the servicelab software lag or the actual plc is not getting the signal for 350msec. I guess that would be my main concern. I definitely don't want to make the process slower by waiting for the signal.

For wireless I was planning on using battery power for the sending unit. For inductive coupling the way I understand it the power goes through the unit.

 

[GaryS]

dos the carriage move back and forth in a straight line ?
what is the total travel distance
is the travel path ever obstructed
you have just 2 red switches correct
i assume you have power to the carriage some how
or maybe just a battery pack
I would contact Banner and see if you could use 2 long range laser sensors and switch the transmitter on / off with the reed switch and use the receiver to controller input

Just a thought

 

[stayclashy80]

Yes carriage moves back and forth in straight line. The reed switches or inductive prox switches are sensing a pusher flap on the carriage that is either open or closed. I don't think there is room or the correct angle to get a laser in the spot to detect the position of the flap. I'm currently looking at banner products 173566 and 192692. My main concern is how long it takes for the signal to get to the plc. Wondering if anyone else has used something different than a hard wire and energy chain and what works. Another thought was using a cable reel instead of the energy chain to have a large bend radius if the timing on the wireless is a problem.

 

[rQx]

There are very flexible cables availabe for robotics etc I think you can find a cable that fits your application unless the construction is not good

 

[GaryS]

I wasn't thinking of using the laser to sense the pusher just as a transmitter using your existing reed switch to turn n / off the laser transmitter 2 transmitters the receivers would be mounted at the end of the rails transmitter on the receiver receives a signal and turn on an input.
i know with banner they have long distance photo senors that mare modulated so if you have 2 sensor's close together the will not cross talk
of course it depend on you having power on the carriage
you could also use a power rail to supply power similar to whats used on cranes or monorails for power depending on the speed
this would be an interesting project to work on

 

[_Dock_]

I would call Igus and get ahold of a local rep. Ours around here is really good. 3 months is really poor and sound like a bad application. Those guys deal with energy chain and flex cable everyday. Let them take a look at it.

 

[stayclashy80]

In response to Gary -
Ah I see what your saying, using the laser to transmit the data. Hmm that sounds cool. Yeah I haven't used those before but noticed they do have some here at my new plant. Needing power on the carriage still seems to be the problem like your saying. I don't know anything about sending power through the rails but that seems like an endeavor. My current plan is to install one wireless set and collect data for a month and compare it to my current hardwire setup and see how good it works before actually trying it live in the automation.

In response to Dock -
Further investigation into our current setup I believe we have the wrong sized energy chain with too small of a bend radius. Looking through all the specs of energy chain cables we have used in the past I think we have used cable that should work if we had the right energy chain. If my wireless option doesn't work I'm going to go for a larger energy chain or cable reel.

Thanks everyone

 

[GaryS]

a question how are you moving the carriage do you have a drive motor or are you pulling it with a cable

for power coupling to the carriage you may want to look at these they should have what you need
https://www.conductix.us/en
cables, power rail, collector systems the even have an inductive power system for contact less power connections
worth checking out

 

[thingstodo]

Not sure how to word the title but here's my scenario. We have a carriage that moves at high speed with an energy chain and the cable bends in a small radius. We are having issues with the cable failing every 3 months. We have tried many different types of high flex cables and none have worked so far. Currently using a 113302 - LÜTZE SUPERFLEX® PLUS type cable. My thought is to go away from physical cable and do wireless or inductive coupling. The application is just 2 reed switch inputs on a pneumatic actuator. I have used Banner and phoenix wireless in the past but nothing that moved this fast. I am also intrigued by inductive coupling but not sure how the signal would be transmitted with the 2 sides moving. Any advice would be appreciated. Very new to this site so I will apologize now if this is not a topic discussed here. Thanks

I used a banner wireless gateway at 900 MHz on a railcar moved/indexer application. It sort of worked. We have a bunch of radio interference, so I missed some pulsed signals. Our local banner guys were no help. We don't buy much banner stuff any more.

It has since gone hardwired with an energy chain. We beefed up the mechanical specs on the chain ... so it has a larger bend radius .. so we have many festoon-style cables to choose from.

I am a bit paranoid about radio. I use it for information signals only. No control. Nothing that puts anyone into harm's way.

If you go radio, there are low-latency systems that have fast detection of signal loss (better than a heartbeat). There are others on the forum that know more about this than I do. My opinion is go with non-proprietary, UDP based. It's a broadcast style rather than a connection style. That said, I have no part numbers to give you