I just received the MEGA-BAS board and have 10K temp sensors connected to the inputs. I've used megabas to set the adc inputs to setting 2 for 10k. Using the same temp sensor I'm seeing ~13k on inputs 1 and 2 while inputs 3-8 are showing the correct ~11k value. With the sensor disconnected on any input I see a reading of 60.000.
I've tried setting the inputs back to 0-10v and calibrating them to 2v and 8v reference points. I've also tried updating the firmware with update64. While the voltage for all inputs reads correctly I have not been able to get inputs 1 and 2 to read the correct resistance.
Any suggestions?
Is there an offset that can be adjusted for the 10k reading? When I read the values in 0-10v mode with nothing connected I see the following. Inputs 1 and 2 appears to be offset by this amount.
pi@localhost:~/megabas-rpi $ sudo megabas 0 incfgwr 1 0
pi@localhost:~/megabas-rpi $ sudo megabas 0 incfgwr 2 0
pi@localhost:~/megabas-rpi $ sudo megabas 0 incfgwr 3 0
pi@localhost:~/megabas-rpi $ sudo megabas 0 incfgwr 4 0
pi@localhost:~/megabas-rpi $ sudo megabas 0 incfgwr 5 0
pi@localhost:~/megabas-rpi $ sudo megabas 0 incfgwr 6 0
pi@localhost:~/megabas-rpi $ sudo megabas 0 incfgwr 7 0
pi@localhost:~/megabas-rpi $ sudo megabas 0 incfgwr 8 0
pi@localhost:~/megabas-rpi $ megabas 0 r10krd 1
2.382
pi@localhost:~/megabas-rpi $ megabas 0 r10krd 2
2.393
pi@localhost:~/megabas-rpi $ megabas 0 r10krd 3
0.007
pi@localhost:~/megabas-rpi $ megabas 0 r10krd 4
0.007
pi@localhost:~/megabas-rpi $ megabas 0 r10krd 5
0.007
pi@localhost:~/megabas-rpi $ megabas 0 r10krd 6
0.007
pi@localhost:~/megabas-rpi $ megabas 0 r10krd 7
0.007
pi@localhost:~/megabas-rpi $ megabas 0 r10krd 8
0.007
pi@localhost:~/megabas-rpi $ sudo megabas 0 incfgwr 1 2
pi@localhost:~/megabas-rpi $ sudo megabas 0 incfgwr 2 2
pi@localhost:~/megabas-rpi $ sudo megabas 0 incfgwr 3 2
pi@localhost:~/megabas-rpi $ sudo megabas 0 incfgwr 4 2
pi@localhost:~/megabas-rpi $ sudo megabas 0 incfgwr 5 2
pi@localhost:~/megabas-rpi $ sudo megabas 0 incfgwr 6 2
pi@localhost:~/megabas-rpi $ sudo megabas 0 incfgwr 7 2
pi@localhost:~/megabas-rpi $ sudo megabas 0 incfgwr 8 2
pi@localhost:~/megabas-rpi $ megabas 0 r10krd 1
60.000
pi@localhost:~/megabas-rpi $ megabas 0 r10krd 2
60.000
pi@localhost:~/megabas-rpi $ megabas 0 r10krd 3
60.000
pi@localhost:~/megabas-rpi $ megabas 0 r10krd 4
60.000
pi@localhost:~/megabas-rpi $ megabas 0 r10krd 5
60.000
pi@localhost:~/megabas-rpi $ megabas 0 r10krd 6
60.000
pi@localhost:~/megabas-rpi $ megabas 0 r10krd 7
60.000
pi@localhost:~/megabas-rpi $ megabas 0 r10krd 8
60.000
Hi,
The firmware also supports calibration for the resistance inputs, but the drivers were not updated.
Let me add calibration support for the resistance input, which will also take care of the offset.
In the meantime, please let me know the version printed on your card to check the hardware.
Thanks for looking into this ! The hardware version is 5.1 and the firmware is 2.05. Below is a picture of the hardware setup.
Hi,
I found the problem and released a new firmware version 2.06.
About the resistance calibration, it is not working properly, so it will take me more time to work on, probably a new firmware release.
I can confirm firmware 2.06 fixed the issue. Thanks for the quick turnaround on the weekend!
Thanks for the confirmation.
A new firmware(1.07) and megabas(1.2.9) version were released to support the calibration for resistance measurement.
Thanks for adding the resistance calibration! I updated the firmware and software to the latest version and see the new commands. I should have time in the next week or so to test it all out.
