Unable to connect to UM-7 AHRS

[Naveen]

Hello,
The device is being detected as USB serial port on COM6 in my deveice manager which is also visible in the Redshift Serial interface. However, upon trying to connect to the AHRS, I get the following errors successively.
“Received packet with bad checksum. Packet discarded.
Error: Timeout while communicating with sensor.”
Note: The LEDs on the UART to USB and on the AHRS are lit.

Further, I tried communicating with the AHRS with Matlab serial communication and i did succeed in getting the data but along with a lot of crap. A sample of the data is as follows:

ïX%Ñ ÿ× D‡ � HsnpìV D‡
hôH»ø D‡
h XÿŸ D‡ pBRZZD‡
hsnpðaÀ
¨Z?Y¯§¿—ñŽD‡
h¿<<þ>õ”9¾ü¹D‡
h¾ºÂã?w¿³[HD‡ p³snpÔpð=ïX%Ë ÿýÿþÿÙ D‡
h
snp̉¾^ú¾ZÁ=ü/
snpìV
D‡0ô0¯ø D‡0 XÿŸ D‡ pBRopD‡0
|snpðaÀ*ð?�Ƥ¿†{DD‡0¿<./>õå¾ü¬eD‡0¾ºÂã?w¿³[HD‡ pqsnpÔpð=ïX%Å ÿÕ D‡Ò$PCHRP,1080.375,0.000,0.000,0.000,-44.33,-46.85,106.19,*7F

$PCHRA,1080.375,-44.33,-46.85,106.19,*6C

$PCHRS,0,1080.375,-2.35,0.79,-1.07,*6E

$PCHRS,1,1080.375,-0.7354,0.4803,-0.4937,*60

$PCHRS,2,1080.375,-

Any help in this regard will be greatly appreciated.

[MichaelKeymaster]

Hi Naveen,

Sounds like a driver issue, did you install the latest FTDI drivers from the FTDI web site?

Regards,
Michael

[MichaelKeymaster]

Naveen,

Also looks like you have NMEA packets and binary data being transmitted?

Regards,
Michael

[Naveen]

Hello,

Thank you for the quick response, Michael. I have installed the drivers found on this link as an administrator and the the device is visible with no warning symbols in the device manager. Is there anything else to ensure that the driver is not an issue? When I could first connect the AHRS to the PC, I remember that NMEA data packets were transmitted at 0 Hz and i was only reading the processed data packets. Please tell me if I can be of further helpful by providing more information about the problem.

Regards,
Naveen.

[MichaelKeymaster]

Hi Naveen,

It definitely seems like you are transmitting NMEA type packets, anything starting with a “$PCHR…” is a NMEA packet type.
Can you please turn these off using the serial interface software, and let me know if this helps.

Regards
Michael

[Author]

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