TEC Cooler Section - Profile Override Option (for QHY174M-GPS)

[Asteroid(6183)]

Robin:

I use SharpCap 4.? with my QHY174M-GPS camera to record asteroid occultations and to do astrometry on asteroids. With the GPS timestamp automatically embedded in the frame header of each exposure, this is an excellent camera for both projects.

As many are aware who use this camera, and as you know, you need to calibrate the start and end of exposure with this camera and save each calibrated exposure setting in a profile. Currently I have about 3 dozen such profiles currently saved. When you save a profile, one of the parameters that gets saved is the temperature setting of the TEC cooler.

I use the camera in a very wide range of outside tempertures ---- from -10F to 80F. Depending on the situation, I may want/need to use the camera most (if not all) of the night set at a specific TEC cooler temperature. I also change exposure settings very frequently during the night.

If I record all my (3 dozen) profiles with the TEC set to say, 5 degrees C, and I find I have the need to chill the camera down a bit further (to say, 0 degrees C), I can do that by manually altering the TEC temperature setting. But -------- If I decided to revise my exposure setting and load another profile, the TEC gets reset back to the setting that I have for all profiles (which is 5 degrees C). I find myself constantly messing with the temperature setting -- which I suspect really isn't good for the camera (with the chip temperature going up and down so much). It's also simply a ROYAL PAIN.

May I suggest that there be an added option in the TEC temperature control section that might simply be a "checkbox" that says something like; "Override all profile temperature settings". When this box is checked, you can now set the TEC to whatever temperature you want and any subsequent loading of another profile will now have that profile's temperature setting IGNORED, and the camera will remain at the temperature you have manually set (and desire for all exposures). So now I would be able to load ANY of the 3 dozen profiles I have, and the camera's TEC temperature setting would remain constant at my desired temperature setting for the night.

I would find such a feature -- TREMENDOUSLY -- helpful.

George

George Viscome
Rand Obs II - MPC W71
Lake Placid, NY, USA

[admin]

Hi George,

if you are handy with a text editor then you can just edit the saved profiles and remove the things that you don't want in them...

So... for all the ones with exposures/calibrations, edit the files and remove the lines that record the target cooler temperature.

Then, when you load those profiles it will set exposure, calibration, etc, but will not change the temperature settings.

Similarly, you could create profiles with different temperatures in them and remove all the other stuff in the profile file - that leaves you with a profile that will only adjust the temperature.

You can find the files to edit by using the 'Manage...' button on the capture profile control and then the 'Show on Disk'.

cheers,

Robin

[Asteroid(6183)]

Robin:

Hmmm... I've yet to try your solution but it seems it should work. I don't mind doing a 1-time edit of my 3 dozen profiles (deleting the TEC cooler setting in each). It then seems that when I first start up SharpCap, I can set the TEC cooler at the temperature I desire (for the night) and changing profiles won't (-can't-) change the TEC temperature setting that I initially set. Great!!!
I'll only reply back if I have problems. If no further message, then it worked!
Thanks!!

George

[Asteroid(6183)]

Robin:

I greatly appreciate your reply on my TEC cooler temperature issue.

I did give your suggestion a try. I edited all 35 of my QHY174M-GPS camera (calibrated exposure) profiles and removed the 3 lines that refer to the TEC cooler. Those lines being:
* Temperature=XX.X (the temp of the chip at the time of profile creation)
* Target Temperature=10
* Cooler Power=0

I then saved all 35 profiles and renamed each starting with the letter "T". So now I have 70 profiles(!)

Your suggestion works --- "Sort of".

My (unedited) Default Profile (loads at SharpCap startup) starts the camera with the TEC Off ("Cooler Power=0"), and with a "Target Temperature=10". After the camera loads, I can then manually lower the temperature directly in the Cooler Section. Lately I've lowered it to 5 degrees C. Now I can load any of my profiles (those new ones starting with "T"), and the TEC does '''remain''' where I had manually set it (5 degrees C).

But.................

Upon loading a different ("T") profile, as the profile loads, I can hear a power load on the camera (the fan slows), and the displayed cooler temperature takes a nosedive (to around 0 degrees C). The % power to the cooler also briefly goes up. Upon completion of the profile load, the temperature of the chip returns to 5 degrees C.

Even if I command SharpCap to reload the same profile I currently have running, the TEC temperature momentarily takes this nosedive to around 0 degrees C. I can see the power (%) momentarily go up also. But then it stabilizes at my desired 5 degrees C after the profile has completed loading.

So yes, removing all references to the TEC temperature in a profile allows you to initially manually set the TEC at your desired temperature for the night, but as you load a new profile, the chip momentarily gets hit will a 'command' to chill further than I desire. Again, not a good thing for the chip... and I switch profiles very often during the night.

Is there a way to not have the chip take this momentary "chilling/power hit"?

As mentioned before, I would love a way where the TEC temperature could be set manually - which would ""override"" (ignore) any Target Temperature setting in a profile.
In my old SBIG ST-7, the TEC cooler setting was completely independent of my exposure choices. (This is really the ideal).

Thanks,

George

George Viscome
Rand Obs II - MPC W71
Lake Placid, NY, USA

[admin]

Hi George,

if you are using SharpCap 4.1 beta then go the to 'Cameras' page of the settings and uncheck the option 'Resend cooler power to camera at camera startup' in the 'QHY Cameras' section. I think that will fix the issue with the power spike you are seeing. I can't quite recall if that option is present in 4.0 or not - it might be. Unfortunately a number of QHY cameras need to have the cooler 'woken up' when the camera is started or the mode is changed, otherwise they tend to start up with the cooler off even if the program has configured it to be on. The wake up consists of changing the target temperature and then changing it back (or setting the power to maximum and then back if in manual power mode). Doubly unfortunately there is no way to tell which models do and which do not need this tweak, hence the option.

Unfortunately the capture profiles feature was designed saving and restoring all camera settings at once, so it requires the sort of manual editing I suggested to skip restoring the thermal settings. I'm reluctant to add special cases for not restoring thermal settings, because the danger of that is that someone else comes up with an equally good reason not to restore some other group of settings or two, and then you end up with a confusing mess of special case settings... Anyway, for now I am only fixing bugs for the 4.1 release, so I will not be adding new features for a while yet

cheers,


Robin

[Asteroid(6183)]

Hi Robin:

Thanks for the suggestion - which I just tried.

FYI, I'm using v4.0.9538, and indeed it has the 'Resend cooler power to camera at camera startup' checkbox for QHY cameras. Alas... When I went to uncheck the box,..... it was already unchecked. I even tried checking it, and later unchecking it again, but in both cases, the "power hit" (when changing profiles) remained.

I'll mention that at times I have gone to manually edit the Target Temperature in the thermal controls section and I believe I momentarily cleared the value of the Target Temperature -- at which point a value of -100 degrees C (!!!) appeared (!!!). Talk about being shocked to see such a value!
Is there something in the code that if the program doesn't see a value in the Target Temperature, it defaults to this value? This might explain why, as I switch profiles (profiles that have all temperature info edited out), that I momentarily get a cooler "power hit" (I see the cooler power take a nosedive).

Admittedly, the power hit is brief as the next profile loads, so the chip never sees -100C (Amen! - it drops maybe 5 degrees C), and it quickly returns to my desired temperature. But it still takes a notable hit.

I am concerned that, if I'm doing a mobile observation, and running off battery power, that the momentary power surge being applied to the camera will cause a battery overload to trip, shutting down all power. Plus, it's not good for the chip.

Any other thoughts on what I might try to allow Target Temperature to be independant of switched profiles (exposures) - and stay constant?

I (we) all greatly appreciate all you do to make SharpCap such a great camera control program. Thanks.

George

George Viscome
Rand Obs II - MPC W71
Lake Placid, NY, USA

[admin]

Hi George,

I've had a bit of a think about this and since you already have the 'resend cooler' option off, it's quite possible that the cooler glitch is coming from the SDK when the camera is restarted on loading a new profile. It may be worth trying the new SharpCap 4.1 beta (soon to be released as SharpCap 4.1). 4.1 is smarter about loading capture profiles and will not restart the camera unless it is necessary. For instance, if the profile load is just going to change controls like exposure, gain, etc, then there will be no restart. There still will be a camera restart for changes of things like capture area, binning, bit depth and so on.

cheers,

Robin