Introduction¶
The AuxTel CCD has been successfully operated at Cerro Pachon and is taking astronomical spectra and images. This document details the power-up and power-down sequences to make sure the CCD operates. This assumes that you are operating within the LSST-WAP network at Cerro Pachon or in La Serena, although this can be run from outside using VPN.
Getting Started¶
The first step is to make sure the CCD power supplies are on and set to the correct voltages. The necessary power supplies are shown in this image. At a minimum, the three CCD power supplies, the back-bias supply, and the auxtel-hcu01 computer all need to be powered on.
Figure 1. AuxTel power rack
These images show the correct voltages on the three CCD power supplies, each of which provides three voltages. This power is supplied to the WREB board, the OTM board, and the fan. The power is then regulated by the WREB board before being applied to the CCD.
Figure 2. CCD Power Supplies
Once you have verified that these are powered up and have the correct voltages, you can proceed to the next step.
Setting up the necessary connections¶
There are multiple ways to do this, but the procedure I have been using is as follows:
- Login to auxtel-mcm, using ssh -X -Y yourname@auxtel-mcm.cp.lsst.org
- Then launch the ccs-console, using ./ccs-console&
- If, like me, you have an M1 Mac, then the ccs-console will launch with a black screen. You can fix this by launching ccs-console with the following options: ccs-console -Dsun.java2d.xrender=false -Dsun.java2d.pmoffscreen=false&
- The ccs-console should then appear in an X-window. You will need to launch the ats-power tab in the CCS Subsystems pull down menu. It should then look like Figure 3.
- At this point, you can view the voltages, but not make changes. To enable changes, you need to set ats-power to a higher level. Do this by going to the CCS Subsystems tab and the ats-power Command and lock browser. Then set the level to 2 and return. Note that this will lock ats-power and you will subsequently need to unlock it when you are finished.
- Then launch the ccs-shell, using ccs-shell.
- We need to run engineering level commands, so you need to run the following two commands:
- ccs>set level ats-fp 10
- ccs>ats-fp switchToEngineeringMode
- At this point you are ready to proceed to the following sections.
Figure 3. ccs-console screen with ats-power module.
Powering up from a completely cold state¶
Assuming you are powering up the CCD from a completely cold state where all power is off, run the following commands:
- In the ccs-console ats-power tab:
- Turn Fan on
- Turn OTM on
- Turn Seq. Power on
It is possible to take an image at this point, even though the CCD is not powered up yet. What this image should look like is shown in the next section.
- In the ccs-shell, run:
- ccs>ats-fp powerCCDsOn
This command should run, and the CCD should power up successfully.
It is suggested to take some images at this point to make sure everything is connected, before turning on the HV bias. Representative images are in the next section.
Once you are satisfied with the images, you can turn on the HV bias. This should not be done unless the CCD is cold. To turn on the HV bias, run the following steps:
- In the ccs-console ats-power tab, turn HV Bias On. This applies the HV bias to the WREB board, but not yet to the CCD.
- In ccs-shell run: ccs>ats-fp/R00/RebW setBackBias true . This applies the back bias to the CCD
Note that both of these steps must be performed to turn on the HV bias. The CCD should now be powered up and ready to run.
Representative images during power up.¶
If you take an image before running atsInit.py, the CCD is not really on and connected, so you are just reading out noise. However, this is useful to verify that images are being taken and stored. An image at this point should look somthing like this:
Images taken while the CCD is warm and without back-bias can look quite ugly. Here are some representative images to compare with:
Powering up the CCD when Seq Power is already on¶
If the Seq Power is already on, then we know the WREB is still in the state where the parallel clocks are enabled. In this case, all that is required to power up the CCD is the following:
- In ccs-shell, run: ccs>ats-fp powerCCDsOn
This command should run, and the CCD should power up successfully.
- In the ccs-console ats-power tab, turn HV Bias On.
- In ccs-shell run: ccs>ats-fp/R00/RebW setBackBias true
Note that both of these steps must be performed to turn on the HV bias. The CCD should now be powered up and ready to run.
Powering down the CCD, leaving Seq Power on¶
To power down the CCD, leaving the WREB Seq Power on, do the following steps. This should be the normal sequence for powering down the CCD:
- In ccs-shell run: ats-fp/R00/RebW setBackBias false
- In the ccs-console ats-power tab, turn HV Bias Off.
- In ccs-shell run: ats-fp/R00/RebW powerCCDsOff
The CCD is now powered down, but the WREB is still powered up.
Powering down completely¶
If, for some reason, you want to completely power down the entire camera, do the following steps after completing the above section. Note that if you then want to power up after this, you need to follow the “Powering up from a completely cold state” section above.
- In the ccs-console ats-power tab, turn Seq Power off
- In the ccs-console ats-power tab, turn OTM Off.
- In the ccs-console ats-power tab, turn Fan off.
The system should now be completely off.
Removing the locks¶
When you are done with whatever you are doing, you need to remove the locks. Run the following commands in the ccs=shell:
- ccs>ats-fp switchToNormalMode
- ccs> unlock ats-fp
- ccs> unlock ats-power