RFID Tag Reply Time?

"The S2000's complete read cycle is made up of:

[Sync-time + Charge-time + Response-time + Housekeeping-time + Delay]

Synch-time depends on how the reader's synchronization is configured; the Charge-time is configurable (default is 50 ms); the Response time is typically 17 ms but will vary slightly depending on the number of '1's versus the number of '0's in the response; the Housekeeping-time is typically 3 ms but slightly longer whenever a tag is read; and the Delay is by default 0 ms but again is configurable.

Wireless Synchronized (Default). In this mode the Synch-time is variable and changes between 1 ms and 70 ms. It is typically:

[20 ms + 50 ms + 17 ms + 4 ms + 0 ms] = 91 ms]

But in environments where noise might be interpreted as another reader:

[70 ms + 50 ms + 17 ms + 4 ms + 0 ms] = 151 ms

Master/Slave synchronization (Without acknowledgement). In this mode the Sync-time is zero and represents the fastest reading cycle.

[0 ms + 50 ms + 17 ms + 4 ms + 0 ms] = 71 ms "Source(s):http://www.ti.com/rfid/shtml/cust-suppor…
Source....

Thanks, but...
What is an 'S2000' ?. Is that a tag or a tag/reader system or what?
Charge time?.. charging of what from what?
configurable what, which how?

That's the sort of info that got me confused enough to ask the Q in the first place
Del

This would be a typical setup, chip, reader, module, antenna...The communication time through each phase....but there are a lot of variables to consider....If you are writing directly to your smart card the variations would be similar, excluding perhaps temperature extremes.....Distance, external noise, as well as the cycle completion time and reset for the reader....I am not an expert in this area, but the parameters would be better understood with some testing perhaps, depending on how far you plan to push from the known and unknown capabilities of this system....

Wow, Solar Eagle takes the answer to a new level! Good answer!

I was recently asked to consider RFID tags as an alternate to a photo eye. It didn't take me long to demonstrate that the RFID tag response had a lot of variation which the application could not tolerate. I was glad to let that one go.

I'm not pushing photo eyes but we did have to change the type to something with a lot more resolution to solve it in our case.

I would delighted to know more about the problem that purrrrr-plexes our favorite kitty. But I really do understand that some things just have to remain undisclosed.

I have a tag sitting very close to the RFID module which will talk to it.
Once ever 15minutes or so the module is woken up from power down mode, it sends a 'read tag' command which the tag responds to.

The delay between sending the command, (4 bytes of data at 115200 baud) and the tag responding is what I'm after...
I don't see how there can be any significant 'synchronisation delay' as there is very little to sychronise to! The Tag will either catch the command or it wont, no second chance until 15 mins later.

Parameters like 'charge tim' etc are pretty meaningless unless explained...

That's what I meant about information overload from Google....
Maybe I didn't make the question explicite enough...
Del

I don't mean to intrude, but I wondered if you had ever encountered or had the opportunity to use a photo optic transceiver device for wireless communication.

I had never encountered them until I was involved on an AGV (automatic guided vehicle) project. It solved so many problems that usually plague RF devices.

They were fairly easy to install and we have never had a problem since. It almost makes me want to be Japanese.

Well explaining things out of context is usually problematic, but the charge time would be the time that it takes the 'power up'(charge cap) to send signal response...Without all the details of the system it makes no sense to try and guess the configuration and individual times of each step....that's why I gave you a 'for instance' so you could approximate the response time....The link I gave gives a wealth of info....perhaps a call in might help...

Here's a forum, you might find helpful....

http://e2e.ti.com/support/low_power_rf/f/667/t/171596.aspx

Nice link...
Thanks

Del

Not sure what equipment you are working with but you may need to edit the tag polling table in the HIM/OUI configuration file(s).

In the systems I am familar with the response time is a product of the HMI/OIU polling table that is configurable, the communications time base that is not configurable, and the PLC or DCS operating system clock that also is not configurable.

If you have this editing capability be sure to eliminate unused/unassigned tags and limit the size of the tag register so that the scan time is minimized.

Many times it takes quite a bit of time to fine tune the table to attain best case response time.

There are many different types of RFID system and most of the time which type to use will be dependent on your particular application? By communication alone, it's either a full duplex or half duplex time. It can also be a passive or active or a combination of them all? The transmitted / received data requirement can also vary in length and affect youe communication response time, sampling time and the total monitoring capacity of a given system?

As an example in a hospital application for infant abduction security and monitoring, the RFID that was selected only transmit a byte of data. It is past responding but only monitor whether the tag is within a given range or not! That system was very different for monitoring a highly mobile IV pumps application. With this type, I have the whole hospital beside being covered by an RF signal on all floors, the data streams are also long, several kilobytes, containing the pump ID, PM due and current location!

I wish you luck since it is not an easy and simple task to do and depending on the application, it may also be a very expensive endeavor!