Yes, you can connect the +/-15V on the rodeostat to the +/-12V on the multiplexer.
Earlier revisions of the Rodeostat used a +/-15V DC-DC converter to provide the power rails for the op amps on the Rodeostat. Whereas, more recent revisions us a +/-12V DC-DC converter. The multiplexer is labeled to match the more recent versions of the Rodeostat. However, the multiplexer will operate fine on +/-15V.
No +/- 0.00009uA (90 picoamps) is too low for the Rodeostat to measure.
I've put a new version (0.6) of the colorimeter software up on the download site here https://bitbucket.org/iorodeo/colorimeter/downloads/colorimeter-v06.exe
This is an upgrade of the software from Python2 to Python3 and from PyQt4 to PyQt5. It was a pretty big upgrade and there could still be some bugs lurking. If you run into any let me know and I will try to deal with them as quickly as possible. However, supporting the Python2/PyQt4 version of the colorimeter software was starting to get to be too difficult so I really needed to upgrade.
I bundled the python software into a single executable using pyinstaller. The final executable came out kind of large (200MB) which results in a bit of a slow application launch. I'll see if I can reduce the size in the future, but I didn't want this to stand in the way of getting you something to work with.
--Will
I've put a new version (0.6) of the colorimeter software up on the download site here https://bitbucket.org/iorodeo/colorimeter/downloads/colorimeter-v06.exe
This is an upgrade of the software from Python2 to Python3 and from PyQt4 to PyQt5. It was a pretty big upgrade and there could still be some bugs lurking. If you run into any let me know and I will try to deal with them as quickly as possible. However, supporting the Python2/PyQt4 version of the colorimeter software was starting to get to be too difficult so I really needed to upgrade.
I bundled the python software into a single executable using pyinstaller. The final executable came out kind of large (200MB) which results in a bit of a slow application launch. I'll see if I can reduce the size in the future, but I didn't want this to stand in the way of getting you something to work with.
--Will
I've put a new version (0.6) of the colorimeter software up on the download site here https://bitbucket.org/iorodeo/colorimeter/downloads/colorimeter-v06.exe
This is an upgrade of the software from Python2 to Python3 and from PyQt4 to PyQt5. It was a pretty big upgrade and there could still be some bugs lurking. If you run into any let me know and I will try to deal with them as quickly as possible. However, supporting the Python2/PyQt4 version of the colorimeter software was starting to get to be too difficult so I really needed to upgrade.
I bundled the python software into a single executable using pyinstaller. The final executable came out kind of large (200MB) which results in a bit of a slow application launch. I'll see if I can reduce the size in the future, but I didn't want this to stand in the way of getting you something to work with.
--Will
@aufdenkampe @wiroon @Peteea6 @aufdenkampe
I've put a new version (0.6) of the colorimeter software up on the download site here https://bitbucket.org/iorodeo/colorimeter/downloads/colorimeter-v06.exe
This is an upgrade of the software from Python2 to Python3 and from PyQt4 to PyQt5. It was a pretty big upgrade and there could still be some bugs lurking. If you run into any let me know and I will try to deal with them as quickly as possible. However, supporting the Python2/PyQt4 version of the colorimeter software was starting to get to be too difficult so I really needed to upgrade.
I bundled the python software into a single executable using pyinstaller. The final executable came out kind of large (200MB) which results in a bit of a slow application launch. I'll see if I can reduce the size in the future, but I didn't want this to stand in the way of getting you something to work with.
--Will
@aufdenkampe @horseflesh @RRobertson
I've put a new version (0.6) of the colorimeter software up on the download site here https://bitbucket.org/iorodeo/colorimeter/downloads/colorimeter-v06.exe
This is an upgrade of the software from Python2 to Python3 and from PyQt4 to PyQt5. It was a pretty big upgrade and there could still be some bugs lurking. If you run into any let me know and I will try to deal with them as quickly as possible. However, supporting the Python2/PyQt4 version of the colorimeter software was starting to get to be too difficult so I really needed to upgrade.
I bundled the python software into a single executable using pyinstaller. The final executable came out kind of large (200MB) which results in a bit of a slow application launch. I'll see if I can reduce the size in the future, but I didn't want this to stand in the way of getting you something to work with.
--Will
The first thing the software does is send the potentiostat command to get the hardware variant from the device. It looks like this command is failing for some reason. The "json.loads" in the error message makes me think that it is not receiving a proper response to this command from the device. This generally happens when either the teensy has not been programmed with the firmware or if the firmware on the teensy has been overwritten for some reason.
Could you send me the complete set of error messages along with the commands you sent. This will help me diagnose this issue.
OK. But just as a check. Close Spyder and all ipython consoles that may be running, etc. Close anything the might have an open connection to the device. Then open a command line and run the python script. Do you still get the access denied response?
Are you trying to run it from the Spyder ipython console? If so you may be creating multiple instances of the serial device object which would be why you are getting the access denied error. A few other users have hit this issue as well. The easiest way to check this is to run the python program in the standard fashion from the command line instead of from inside the ipython REPL. Do you still have this issue when running from the command line?
Could send me a few more details on your setup and how you are trying to connect to the Rodeostat.
What OS are you using? I'm guessing the OS is windows from the "COM" port reference above, but knowing the version of Windows e.g. 7, 10, etc may help me diagnose the issue.
Are you using the Python API or the WebApp?
I can't really help with the arsenic measurement, but I can help you create a Python program for your tests. Could you provide some details regarding the tests you want to perform ?
The get_volt() method returns the current output voltage setting i.e., the value set by the user (perhaps with the set_volt method) for the voltage between the working and reference electrode. Whereas the get_ref_volt() method returns a measurement of the voltage between the working and reference electrode. There is no method to get the voltage between the working electrode and counter electrode.
We do not have a DPV test implemented for the Rodeostat yet. This is something we are planning to add in the future. However, there isn't a specific timeline I can give you for adding this test.
Best,
Will
Hi Greg,
I looks like the access permissions had be set to private. I've change it to public. You should be able to download the file now. You can also access the repository here https://bitbucket.org/iorodeo/ph_meter_firmware
--Will
I'm not sure the exact cause of the "hairyness" the CV's. I do know that it only seems to occur when using certain electrochemical setups. We don't see it with purely resistive loads such as dummy cells or even simple dummy cells with combined resistive and capacitive loads. You can do CV sweeps etc. and no hairiness . So it isn't really a matter of whether or not the potential is fixed - maybe it is some characteristic of the load in the cases where we see the hairiness. It would definitely be interesting to explore the issue. I've been considering designing some more general dummy cell PCBs for testing purposes and I would love some input on designs. It would be great to have a very general dummy cell design which could mimic all sorts of loading situations. In particular, could we find a dummy cell with the correct load characteristics to reproduce the issue? or is this really something to do with the electrochemical cell?
The capacitor in the feedback loop of capacitor of the control amplifier is a compensation capacitor used to improve stability. It is basically providing a high-frequency bypass. The load which the potentiostat is going to be hooked up to is essentially unknown (lots of different variations) so we wanted the control loop to stable under a broad range of conditions. Adding this compensation capacitor was found to help extend in stability over a broader range of conditions without causing a detrimental effect. I don't believe this capacitor is the cause of the hairiness you are seeing.
The compensation capacitors on the transimpedance amplifiers are also for stability. The values have been selected fairly conservatively. So we are probably getting a bit more lowpass filtering then absolutely necessary. For the most part this is more of an issue for the lower current ranges where the resistor in the feedback loop is larger. We've made some nA versions of the Rodeostat where we had to go to larger capacitor values in order to ensure stability. For example, for a +/- 60nA range with a 10MOhm resistor we needed a 100nF compensation capacitor for stability. Again I don't think these capacitors are the issue.
Could explain in a little detail what you installed. I can't think of any relationship between the colorimeter software and iTunes ... so I'm guessing this error might be and unrelated issue.
I'm happy to try and help. Could you explain in a bit more detail the issue you are having?
The LEDs not flashing could still be related to the sensor issue. The firmware cycles through the LEDs one at a time and measuring the frequency of the pulses coming from the light sensor - the frequency of these pulses is proportional to the light intensity. It measures the frequency (or period) for "Samples" number of pulses and then averages to get a get final measure of the frequency (and thus light intensity). If the Arduino isn't receiving the pulses the firmware will error out and so you won't cycle through to the next color. This could explain why you aren't seeing all the LED flashes. Also, you can slow down the LED flashes by increasing the "Samples" number, e.g., increasing "Samples" to 5000 will make the firmware try to measure 5000 pulses and average the results - this will take longer so the LED will remain illuminated for longer.
We can send you a replacement sensor board, arduino shield and ribbon cable. This should cover the bases regarding the sensor unless it is an issue with the Arduino itself. I should be able to have the replacement parts in the mail to you by tomorrow.
Yes, it may indicate an issue with the sensor board, the connection to the sensor, or with the firmware.
Do you get any error when initially connecting to the Arduino? After connecting what do you see in the "Samples" textbox? is it set to 500?
If connecting to the Arduino works OK, but after trying to calibrate with the sensor in room light you get the error "unable to calibrate device: RSP_ERROR: [0, calibration failed]". This means the the Arduino is not able to read from the light sensor.