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kanflo
Voltage is off
Today I've upgraded my DPS5005 to OpenDPS but when I set voltage, the output voltage is off. See following table:
Set,Displayed,Measured 27,25.7,25.59 20,19.04,18.94 15,14.28,14.22 10,9.53,9.48 5,4.78,4.74 3.3,3.17,3.13
I'm attaching original firmware data sets:
3.7V-off.txt 3.7V-on.txt 5V-off.txt 5V-on.txt
Is this a bug or do I need to calibrate something?
You will need to run the calibration script.
The main commands you will need are:
dpsctl.py -C
dpsctl.py -cr
Pull request #120 was useful to me
If you are using the USB adapter that came with the DPS you will need to change the baudrate in your build #135 (9600 works for me)
There is a ticket to add this calibration routine information to the readme #131 (This issue also caught me by surprise when I got my DPS a week ago)
I would like to see your calibration parameters and see if they lineup with mine. If so it might be worth recording them somewhere for future users.
Mine:
Calibration Report:
A_ADC_K = 1.67881917953
A_ADC_C = -117.5
A_DAC_K = 0.664585292339
A_DAC_C = 263.0
V_ADC_K = 13.1308298111
V_ADC_C = -124.792572021
V_DAC_K = 0.0761880800128
V_DAC_C = 3.04274582863
VIN_ADC_K = 16.7254924774
VIN_ADC_C = 20.6332607269
I'm having trouble running it:
Func : calibration (off)
A_DAC : 2
V_DAC : 0
V_in : 12.21 V
V_out : 0.00 V
I_out : 0.000 A
danman@silverhorse:/storage/Projects/opendps/dpsctl$ ./dpsctl.py -d /dev/ttyUSB0 -q
Func : calibration (off)
A_DAC : 2
V_DAC : 0
V_in : 12.22 V
V_out : 0.00 V
I_out : 0.000 A
danman@silverhorse:/storage/Projects/opendps/dpsctl$ ./dpsctl.py -d /dev/ttyUSB0 -C
For calibration you will need:
A multimeter
A known load capable of handling the required power
A thick wire for shorting the output of the DPS
2 stable input voltages
Please ensure nothing is connected to the output of the DPS before starting calibration!
Would you like to proceed? (y/n): y
Input Voltage Calibration:
Please hook up the first lower supply voltage to the DPS now
ensuring that the serial connection is connected after boot
Type input voltage in mV: 12250
Error: protocol error (-3).
danman@silverhorse:/storage/Projects/opendps/dpsctl$ ./dpsctl.py -d /dev/ttyUSB0 -q
Func : calibration (off)
A_DAC : 2
V_DAC : 0
V_in : 12.22 V
V_out : 0.00 V
I_out : 0.000 A
I switched to 9600bps, I can pass more steps but still I cannot finish the procedure. Please see attached log.
Here it is but I have a bad feeling that something went wrong with the device. The output voltage is 0V no matter what I set :( calib2.txt
danman@silverhorse:/storage/Projects/opendps/dpsctl$ ./dpsctl.py -d /dev/ttyUSB0 -q -b 9600 -v
Communicating with /dev/ttyUSB0
TX 5 bytes [7e 04 40 84 7f]
RX 48 bytes [7e 84 01 7d 5e 9d 00 00 00 00 01 ff ff ff ff 00 63 76 00 76 6f 6c 74 61 67 65 00 35 30 30 30 00 63 75 72 72 65 6e 74 00 32 30 30 30 00 38 da 7f]
Func : cv (on)
current : 2000
voltage : 5000
V_in : 32.41 V
V_out : 0.00 V
I_out : 0.000 A
Curious what the calibration report -cr will show. I expect it might be corrupt. Could you dump that for me?
Can you do a --calibration_reset and see if that brings you back to your original behaviour?
Someone else might like to comment. But I believe you should be able to manually set the voltage output via dpsctl.py -c VOUT_DAC=XXX to prove the device is still working.
Enabling the debug calibration plots might be useful to ensure the maths isn't going horrifically wrong: https://github.com/kanflo/opendps/blob/94cb035bade6d2caeb58ba41b2c935aad3b995fd/dpsctl/dpsctl.py#L51-L53
Have you attempted to apply my calibration parameters and see how it behaves?
danman@silverhorse:/storage/Projects/opendps/dpsctl$ ./dpsctl.py -d /dev/ttyUSB0 -b 9600 -v -cr
Communicating with /dev/ttyUSB0
TX 5 bytes [7e 12 32 73 7f]
RX 58 bytes [7e 92 01 00 07 07 86 00 00 00 00 00 00 3f db 43 96 c2 ed 05 1f 3f 26 e9 79 43 90 4e 35 00 00 00 00 00 00 00 00 7d 5f 80 00 00 7d 5f c0 00 00 41 86 16 fb 42 a1 07 c6 b9 73 7f]
Calibration Report:
A_ADC_K = 1.71300005913
A_ADC_C = -118.510002136
A_DAC_K = 0.652000010014
A_DAC_C = 288.610992432
V_ADC_K = 0.0
V_ADC_C = 0.0
V_DAC_K = inf
V_DAC_C = nan
VIN_ADC_K = 16.761220932
VIN_ADC_C = 80.5151824951
VIN_ADC = 1926
VOUT_ADC = 7
IOUT_ADC = 0
IOUT_DAC = 0
VOUT_DAC = 0
Phew... I was starting to be a little bit worried, but now it is in original state:
danman@silverhorse:/storage/Projects/opendps/dpsctl$ ./dpsctl.py -d /dev/ttyUSB0 -b 9600 -v --calibration_reset
Communicating with /dev/ttyUSB0
TX 5 bytes [7e 14 52 b5 7f]
RX 6 bytes [7e 94 01 c4 0e 7f]
danman@silverhorse:/storage/Projects/opendps/dpsctl$ ./dpsctl.py -d /dev/ttyUSB0 -b 9600 -v -cr
Communicating with /dev/ttyUSB0
TX 5 bytes [7e 12 32 73 7f]
RX 56 bytes [7e 92 01 01 71 07 84 00 46 0d dd 01 6a 3f db 43 96 c2 ed 05 1f 3f 26 e9 79 43 90 4e 35 41 52 9f be c2 c9 80 83 3d 93 74 bc 3f ec cc cd 41 85 f7 cf 42 80 39 58 93 e1 7f]
Calibration Report:
A_ADC_K = 1.71300005913
A_ADC_C = -118.510002136
A_DAC_K = 0.652000010014
A_DAC_C = 288.610992432
V_ADC_K = 13.1639995575
V_ADC_C = -100.750999451
V_DAC_K = 0.0719999969006
V_DAC_C = 1.85000002384
VIN_ADC_K = 16.7460002899
VIN_ADC_C = 64.1119995117
VIN_ADC = 1924
VOUT_ADC = 369
IOUT_ADC = 70
IOUT_DAC = 3549
VOUT_DAC = 362
Interesting how
V_ADC_K = 0.0
V_ADC_C = 0.0
V_DAC_K = inf
V_DAC_C = nan
got written to the device. Those calibration plots might actually be helpful in this situation. I guess the maths went funky or the communication got corrupt.
It's strange that during all calibrations the 10% and 90% output never changed. It was always the same value (either 0mV or 4750mV)
Oh wait, so I am not supposed to disconnect my DPS from one power supply and connect to another (so it is off for a few seconds)? I don't have any other variable power supply...
Calibration DONE. Now the output is correct. My calibration report:
Calibration Report:
A_ADC_K = 1.79930484295
A_ADC_C = -95.1757049561
A_DAC_K = 0.623115241528
A_DAC_C = 232.119384766
V_ADC_K = 13.2031030655
V_ADC_C = -81.2796630859
V_DAC_K = 0.0757494047284
V_DAC_C = -0.125067427754
VIN_ADC_K = 16.7640190125
VIN_ADC_C = 81.8370361328
VIN_ADC = 1921
VOUT_ADC = 7
IOUT_ADC = 70
IOUT_DAC = 0
VOUT_DAC = 0
Second calibration with 3.9Ohm resistor:
Calibration Report:
A_ADC_K = 1.51646900177
A_ADC_C = -61.857170105
A_DAC_K = 0.739067077637
A_DAC_C = 219.17300415
V_ADC_K = 13.2118587494
V_ADC_C = -85.1219482422
V_DAC_K = 0.0757377296686
V_DAC_C = -0.163032591343
VIN_ADC_K = 16.8438606262
VIN_ADC_C = 31.3570976257
VIN_ADC = 1922
VOUT_ADC = 7
IOUT_ADC = 70
IOUT_DAC = 0
VOUT_DAC = 0
But it surprises me that even without load it shows 0.043A output current. Is this normal?
I found that I ended up tweaking the values manually to get those perfect 0,0 intersection.
See my comment https://github.com/kanflo/opendps/issues/130#issuecomment-527873355 And #158
IOUT_ADC = 70
A_ADC_K = 1.51646900177
A_ADC_C = -61.857170105
I see your ADC is about 70 with no current (I am assuming you have no current since the voltage output is off)
So the current it reports should be:
70*1.516-61.85=44mA
If this really is 0mA then just nudge the zero offset.
Set dpsctl.py -c A_ADC_C=-106.12