LabView project

Good morning to all.

I'm creating an application in labview for controlling an RFID reader. The RFID reader that I'm using is the Impinj Speedway R420, while the tags are simple near field tags. The objective of this application is the calculation of the position of various RFID tags based on the RSSI. First of all I'd like the reader to send to the algorithm that calculates the position only one reading for each tag and for each antenna per second. I try to explain the results obtained so far.

My application has an outer infinite while loop (that I can stop with the exit button), in which there is an event structure that intercepts the click of the various buttons of the application. The two main buttons are: the start button that enables the TCP connection with the reader and that adds the rospec, and the inventory button that enables the rospec. After pressing the start button the application can, of course, receive the responses to the "delete rospec" and to the "add rospec" messages, and is able to request and receive the configuration of the reader. By the press of the inventory button, the reader is able to receive packets related to the "reader event notifications" and to the readings of detected tags.
As mentioned earlier, my goal is to have, for each second, a single reading of each tag for each antenna. For example:

- id_tag 3 id_antenna 5 time 10sec
- id_tag 3 id_antenna 3 time 10sec
- id_tag 2 id_antenna 4 time 10sec
- id_tag 6 id_antenna 2 time 11sec
- id_tag 7 id_antenna 2 time 11sec
etc. ..

To achieve this result with only two tags, I tried to set the rospec properly. I set the parameter "AISpecStopTriggerType" to "observation Tags", while the parameter "TriggerType" to "Upon seeing N tags observations, or timeout." I set N to 2 and the timeout to 1000msec. Finally, I set the parameter "ROReportTrigger" to "Upon N TagReportData Parameters or End of ROSpec" and N = 2. With this configuration, if an antenna reads two tags, it correctly displays a single reading for each tag, per second. But if I bring near the antenna only one tag, the application displays two readings of the same tag, per second. How do I properly set rospec?
Thank you and sorry for the length of the post (and for my english).

P.S. I saw that my reader implements LLRP Protocol version 1.0.1. In version 1.1, I saw some triggers that seem to be most appropriate to my goal. Could I do a firmware upgrade to take advantage of the new protocol version?

Thanks for the quick response and for the welcome!

I also thought of setting N to 1, leaving the timeout to 1000ms. Unfortunately, in this way, the reader makes only a single reading of one tag every second. If I bring two tags near antenna, the application displays, every second, only one of the two tags (not always the same, probably the one who won the contention). If I don't choose any stop trigger by setting the parameter "AISpecStopTriggerType" and the timeout to "null", the application displays the reading with too high frequency, making difficult an application side filtering. In version 1.1 of the LLRP protocol it is possible to set the "TriggerType" parameter to "Upon seeing N UNIQUE tags observations, or timeout.". I think this would be a solution. In your opinion, by updating the firmware of the reader can I automatically get the new version of LLRP Protocol?

Thanks again for your help.

Great! You have fully understood the problem!

I contacted the Impinj to ask if I get the new version of the LLRP protocol by updating the firmware. I also asked for an account, but I have not received any response yet. I found an updated version of the firmware on a Chinese website, but I'd rather wait for a response from Impinj to be sure I can install a really official firmware.

Great! Glad to help :)