A new System

[Steve Meisel]

does anyone know what the RS stands for?
Tim R

Recommended Standard

Wow! A question on something that I actually learned in class last semester.

 

[dash]

"That would require the operator to change the DeviceNet address"

Why?

I would think that if you went with DeviceNet you could put a small input module in the unit & use a BCD dial to set the "station" number so that your main processor would know that the station has been relocated.

That way the DeviceNet node number would allways be the same, but would report it's point of use back to the system.

Just a thought,

Darren

 

[dash]

Or in some of the stuff we do we use an "intelligent" node (a Wago PFC). That way you can add RS-485 or RS-232 ports (up to 64 per node) and crunch your string data in the Wago (the structured text also gives you very good control over the serial ports). You can also drive an inexpensive serial display from the Wago to provide basic enunciation to the operator of failed reads/writes, assembly problems, display a parts list & decement the list as the operator scans items with a barcode or enters/exits pick bins. Also I have typically found the the serial interface for all the RFID units I have worked with is usually more flexible than the field bus units. So with the structured text in the Wago you are able to create a very efficent process specific "engine" for driving the RFID data in/out of the tags. If the tags are large enough we have even stored the data in an XML format so that if you add/remove data or rearange the data you do not have to go into overload mode to be able to adjust your ERP/MRP (accounting software) interface since the data will be treated more like fields and the length/location of the data becomes independent.

The barcode reader could be used to set the point of use number in the PFC by the operator scanning the new location code on the conveyor system when he plugs the unit in. You could set it up to automatically prompt him/her when they plug the unit in.

Darren

 

[Alan Case]

I would be a bit dubious of any claim that the system would work at the speed you require on DH485. I would be exploring the devicenet option. Regards Alan Case

 

[akreel]

Recommended Standard

Wow! A question on something that I actually learned in class last semester.

Norm and Steve,

My research uncovered something different.

Buried somewhere in the Texas-Instruments archive, there's a document that explains "Recommended Standard" is a commonly accepted misnomer. The answer, according to TI, is "Radio Sector." There is some history of the RS set of electrical standards developing out of HAM radio or something...

Personally, I think "Radio Shack" is a better answer, anyway.

AK

EDIT: Found it. See page 4.
http://focus.ti.com/lit/an/slla070c/slla070c.pdf

 

[Terry Woods]

Hmmm... Interesting challange...

Worst case, it sounds like telling 13 people to scatter themselves about in the three rooms and then having each of them do something. ("Cycle-on-Station" comes to mind, an old Navy reference, as in... "Look what I can do!" - MAD TV).

OK... the units can be moved anywhere among the three rooms. Is it the case that the particular locations within the rooms are absolutely random? Are there any kind of reference points at all?

I get the feeling that these stations are receiving parts from a conveyor system of some kind... is that the case? If so, is the delivery system located in a fixed location? Again, if so, are the transfer points fixed?

Or... are there locally loaded supply bins at each station?

I have an idea... but, I'm done guessing about what the situation really is... more details about the potential layouts would help a lot.

And please... please, please don't say that all operating locations are completely random... that would make things... a bit (a bunch) more difficult.

 

[ndzied1]

I had read the Recommended Standard in "The C Programmers Guide to Serial Communications". I guess they got it wrong... or maybe not all the way right.

 

[akreel]

I had read the Recommended Standard in "The C Programmers Guide to Serial Communications". I guess they got it wrong... or maybe not all the way right.

Who knows? I figure TI's been building the IC chips since day one... Who better to believe?

Maybe RS stands for "Random Speculation."

 

[rsdoran]

As I stated in my earlier post I have provided this info several times. RS is short for Recommended Standard developed by EIA.
http://www.webopedia.com/TERM/R/RS_232C.html

In the early 1960s, a standards committee, today known as the Electronic Industries Association, developed a common interface standard for data communications equipment. At that time, data communications was thought to mean digital data exchange between a centrally located mainframe computer and a remote computer terminal, or possibly between two terminals without a computer involved. These devices were linked by telephone voice lines, and consequently required a modem at each end for signal translation. While simple in concept, the many opportunities for data error that occur when transmitting data through an analog channel require a relatively complex design. It was thought that a standard was needed first to ensure reliable communication, and second to enable the interconnection of equipment produced by different manufacturers, thereby fostering the benefits of mass production and competition. From these ideas, the RS232 standard was born. It specified signal voltages, signal timing, signal function, a protocol for information exchange, and mechanical connectors.

As you can see Radio was not involved in creating this standard.

 

[CaseyK]

Maybe RS stands for "Random Speculation."

I thought we should ask the expert. But he just replied.

I thought the R stood for RON. (rsdoran)

regards.....casey

 

[CaseyK]

I would LOVE to do this project with a GE Fanuc 9030 rack with wireless and VersaMAX micro's at each station.

I can do this project for.....

Oh rats, this isn't a bidding war.

I did something similar with 9030's and MultLin (GE) Relays several years ago, with a combination hardwired and wireless system. The MultiLin's did have an address assigned to them, so location or daisy-chaining was not a problem. we were partially wireless, as some of the facility was over 800 feet out, and another group of equipment was over 4000 feet out.

Worked quite well. Didn't have to make a road trip to sunny Cal. Though, on this cold wet windy March night in Illins, I would consider a trip to the land of Fruits and Nuts.

regards.....casey

 

[akreel]

As you can see Radio was not involved in creating this standard.

Food for thought, Ron:

Here's part of the answer I was looking for.
http://www.tiaonline.org/about/overview.cfm

If you check out the history portion of the page, you'll see EIA/TIA used to be "The Radio Manufacturers Association." So, my comment on HAM radio was off base. Interestingly enough, the organization is still broken up into "SECTORS". The TIA sector is currently responsible for the 232 standard. Interesting, no?

This doesn't prove anything conclusively, not even to me. But, having visited the site, I'm actually more convinced that "Radio Sector" might be right.

Do we have any EIA/TIA members who want to pipe in? Or, does someone want to buy the datasheet to see if it settles the debate?

AK

 

[akreel]

OOPS!!! I must've had a brain-****!

RS stands for "Rockwell Software."

 

[JesperMP]

Lets have a look at those Balluff RFID recievers/transmitters.
Exactly which one(s) are you having in mind.
The ones I took a look at had RS232 (ASCII ?), RS485 (ASCII ?), InterBus, Profibus or DeviceNet capability.

Fine, that means you dont need a special interface card if you pick InterBus, Profius or DeviceNet.

You rule out wireless completely - OK.
There has to be detachable tabs with a length of up to 50 m - OK.

Then I suggest that you pick ProfiBus or DeviceNet, and then let a "station" (i/o modules, RFID module, HMI ? etc..) connect via one and same "drop" cable connection via a repeater.
There should then be a bunch of repeaters to suit the number of possible locations.

Purple = Profibus or Devicenet network.
Green = Ethernet network
R = Repeater

Its simple and inexpensive and it will work.

 

[JesperMP]

Tim R.

Is this by any chance a high-speed application ?
How many parts does the system have to handle per minute ?
How many steps are there in the sequence for each part ?

If it IS a high-speed application, then it will affect how the system must be implemented.