I am attempting to use the M7E RFID reader, with the antenna and cables recommended onsite, using URA 6.2
https://www.sparkfun.com/products/14131
https://www.sparkfun.com/products/14132
https://www.sparkfun.com/products/662
I am powering via USB, and have switched the 0ohm resistor to external antenna setting.
Antenna selected is one, baud rate is 115200
I assumed NA is North America for region, but also tried OPEN.
GEN2 protocol is selected, and the tags I’m using are GEN2 as well
When I attempt to read the RFID tag, I get “The module has detected high return loss and has ended RF operations to avoid module damage”
This occurs at dBm settings from 27 all the way down to 0
It occurs with different tags of different manufacture.
It occurs if I read but do not have a tag present at all
What am I doing wrong?
According to the URA source code this: Excess power detected at transmitter port, usually due to antenna tuning mismatch.
According to the Thingmagic user guide : error 0x505
The module has detected a poor return loss and has ended RF operation to avoid module damage.
Take steps to resolve high return loss on receiver:
Make sure antenna VSWR is within module specifications
Make sure antennas are correctly attached before transmitting
Check environment to ensure no occurrences of high signal reflection back at antennas.
Seems related to the antenna connections.
Antenna is correct, connections are solid, tried using alternate connectors just in case. Put attenuators in line, anywhere from 2dB to 20dB, no success.
what happens if you remove the external antenna and switch back to use the on-board antenna?
Same thing. I’m suspecting something very simple that I’ve overlooked, but can’t seem to find what.
weird… very weird… I wonder whether this is due to the latest 6.2 version of the URA. Somewhere I read before the latest mercuryAPI (and thus URA) should only be used from a certain firmware level on the boards… maybe an earlier URA will work. I will try tomorrow on my M6E. Else the components on your boards could have an issue…
I tested my M6e and URA 6.2 and it worked without problems. Stayed on 5db read power to keep a stable USB, EU3, 115K speed, used a USB/serial which is set to 5V VCC (check that on yours as many are by default 3v3 VCC), onboard antenna.
Maybe check you have the firmware on the M7E V2.1.3 or higher (URA, connect to the M7E, select Status/version info)
Else it looks like a problem with your board, maybe a short circuit on the antenna.
About loss return & VSWR found an attached document to explain that a bit more
ThingMagic_M7E_Power_App_Note.pdf (340 KB)
Cut the trace to set 5V, no change.
I assume you could read the firmware level and if so I can only conclude a problem with your board with the antenna circuit/traces. I would ask for a replacement
Maybe share some pictures about the antenna select and if I do a cold ohm measurement, no power is applied, between GND and the antenna select I get 0.3 ohm. Maybe check that.
else I would ask for a replacement