What does USB3 mean for the contol industry?

BillRobinson

Member
BillRobinson
Join Date
Oct 2006
Location
Sydney, Nova Scotia
Posts
185
NEC announced their new USB3 chip a few weeks ago. This means USB3 is on it's way at a blazing 5 Gbit/s. Will this ever reach the control industry or will be forever carrying around our DB9 serial cables, and crimping/recrimping ethernet cables?
 
BillRobinson said:
NEC announced their new USB3 chip a few weeks ago. This means USB3 is on it's way at a blazing 5 Gbit/s. Will this ever reach the control industry or will be forever carrying around our DB9 serial cables, and crimping/recrimping ethernet cables?
Click to expand...

I think that USB3 will probably similar maximum cable length of USB1 and USB2, which was 3m max as I recall. This is not awfully useful for any industrial application other than programming, and Ethernet is perfectly adequate for most PLC programming purposes - the speed of the processor is more of a limit in most cases than the transfer network.
 
The problem is efficiency

USB is very inefficient. There needs to be better USB chips that have 32 bit interfaces with fewer wait states. Perhap. DMA. Right now the controller must slowly send and receive 8 bits at time. This is a waste of 64 bit CPU that should be transferring data 64 bits at a time with few wait states.

So sure, send data back and forth a 5 Gb/s or whatever the rate and tie up your CPU doing nothing but reading or writing data into and out of a USB chip.
The reality is that small amounts of data will be transferred at the highest rate but there will be plenty of time in between the packets.

You know that the faster you send the data the short the distance will be that you can send it. Is speed everything or would you sacrifice some speed for distance? I don't think USB is good for I/O, yet.
 
With 32 and 64 bit busses being common now, why would USB still be using 8 bits? I'm not an expert on busses or USB but something seems amiss here.
 
That really doesn't mean much in and of itself, especially for I/O on a separate controller...you could imagine synchronized race cars on a two lane highway versus a traffic jam on a six lane one...

godfrey said:
With 32 and 64 bit busses being common now, why would USB still be using 8 bits? I'm not an expert on busses or USB but something seems amiss here.
Click to expand...
 
Omron have had USB 1.1 for some time now. Quite frankly higher than 1.1 is probably not required for PLCs as there is so little data transferring when monitoring, uploading or downloading. I find 1.1 blazingly fast for PLCs.
 
BobB - do you keep any devices permanently attached (panelview, datalogger, etc)...or is this just when you connect a PC to program the PLC (like the traditional serial connection)? The 3m range strikes me as the biggest drawback.
 
I had seen info stating:

  • 15Gbps @ 1 meter
  • 10Gbps @ 2 meters
  • 5 Gbps @ 3 meters
But no mention of distances beyond that which I would guess means we still have that limit. Great for point-to-point but I think Ethernet is still the best route for sustained comms.

I would think pushing all that data would stress out the computer PCI or PCI-E bus as well as the cpu.

OG
 
Beckhoff already have a USB Adapter for their IO blocks. I guess the intended usage is with a PC being the controller.
However, the limitations with USB are so significant, I can see zero justifaction for it in an industrial environment. Maybe in a lab, maybe not.
BillRobinson said:
Will this ever reach the control industry or will be forever carrying around our DB9 serial cables, and crimping/recrimping ethernet cables?
Click to expand...
No, we dont crimp ethernet cables any more. In an industrial application we use either preconfectioned cables, or use industrialised connectors that can be assembled without crimping tools.
 
I have only used USB for programming connections at this stage however I have 1 x 5 metre & 1 x 3 metre cables plugged together and have had no problems - just slowed down a bit. The cables are very high quality ones and have the ferrous filters on them.
Omron have only provided a programming connection at thios stage and not a HMI connection for the USB port on the CP1.
They have provided a network connection TCP/IP for the CJ2H but I have never used a CJ2 at this stage so cannot comment on how it works.
 
What is wrong with crimoing ethernet cables?

I do it all the time. Just need the right tools.

I use the feed thru jacks and crimpers. Makes it esy to line up and crimp.
 
Jesper's mention is the first I've heard of "industrialized connectors". What gives?

The Plc Kid said:
What is wrong with crimoing ethernet cables?

I do it all the time. Just need the right tools.

I use the feed thru jacks and crimpers. Makes it esy to line up and crimp.
Click to expand...
 

Similar Topics

A
Tank level rslogix 5000 program. I’ve got errors on rung 2,3,4. Do u see the problems? Also does my geq n les look right?
Replies
4
Views
192
drbitboy
drbitboy
S
Does anybody have Somachine V4.2 ?
I am trying to connect with a Schneider plc which has a firmware version only available in Somachine v4.2. In Machine expert After taking upload...
Replies
0
Views
110
sherlockmi
S
Bit_Bucket_07
Does anyone recognize these terminals?
They are installed in a control panel that was made in France and are intended for the termination of analog inputs. Each of the red capped...
Replies
4
Views
413
Robb B
R
F
GSV does nothing
So, I'm really just trying to get some experience by practicing with arrays. I'm using studio 5000 v33. I have one rung with an XIC bit that's...
Replies
5
Views
229
Culliham
C
P
What exactly does the BR bit do?
I tried researching but I still don't quite get it. As far as I understood, it's used after a function is called in STL and then if the function...
Replies
1
Views
143
JRW
JRW
Back
Top Bottom