ESI Shutter Troubleshooting

Checking the Software

There is a chance that the problem lies in the software becoming confused. In the event of a mechanical shutter problem images should complete their readout and display on FIGDISP. The shutter may be stuck open or closed, so the data may not look the way you think they should, but you will get images.

If images are hanging and not reading out or not being displayed properly, there may be a software problem. Follow these steps:

  • Run "fix_stuck_ccd" on kanaha. This resets keywords to the state they should be in when there is no exposure in progress. If they report a problem, wait a bit to see if the image resumes readout or display.

  • If things are still bad, run "testAll" on kanaha to check for the health of the communications.

  • Try restarting lickserv/figdisp from the "Subcomponents" submenu of the "ESI Control" menu on the desktop. Again, wait a bit to see whether a readout commences and then finishes.

Resetting the Controller

The controller logic prevents the shutter from operating in many circumstances when it detects an error. To reset the logic it is necessary to power-cycle the shutter controller. A rocker switch for this purpose has been brought the front outside electronics box (box #2). Verify that the rocker switch is indeed set to the ON position. Here are a wide angle shot showing where to look for the power switch and a close up of the switch itself:


Wide angle view of ESI shutter controller power switch
(click to zoom)


Close-up view of ESI shutter controller power switch
(click to zoom)

Mechanical Failure

To start, try using Jason Chin's procedure. This uses the shutter control box, allowing you to simulate or fool the limit switches and fire the shutter even if the real limit switches are not functioning properly, or if the shutter has not made the limit switches.

If the problem cannot be resolved using Jason's procedures, follow this procedure provided by Matt Radovan, UCO/Lick Observatory:

To check the shutter, have someone stand by the instrument with another person in front of the Dashboard GUI. On a kanaha command line, type "s shutstat" and note the output. A working shutter will say something like "closed L" or "closed R". A malfunctioning shutter will probably have either "err" or "?" as one of the states, e.g. "L: out R: ?". "L:in R:err" is actually the reported value during CCD erase and readout. See the shutter keyword table below for the various possible states of the SHUTSTAT keyword.

Take a 10 second non-dark (i.e. "Object," "Line," or flat) exposure. Does the observer hear the shutter move?

Type "s shutstat" again and see whether the state has changed.

If the shutter does not change state then do the following:

  1. Find the little black box that simulates the ccd controller.

  2. Unplug the DB-9 cable from the ccd controller and plug the black box in.

  3. Try and change state with the toggle switch.

  4. Watch the limit lights on the black box. This will tell you what the limit switches on the Bimba are doing.

If the limits are OK then the shutter should be moving.

If the bimbas are not moving when commanded and the limits are being reached, but the CCD is taking funny pictures then try this:

  1. Move all the filter wheels to open positions (either "Clear_S" or "Clear_I" on the GUI).

  2. Put ESI in imaging mode ("Obstype" on the GUI).

  3. Shine a flashlight into the open filter wheel positions and look into ESI. You should be able to see into the camera. Toggle the shutter. What do you see? Has a blade broken off and is floating around in the camera? Does the shutter incompletely open or close?

When the blade is out all you should see is the CCD. NO BLADE WILL BE SHOWING.

Changing Shutter Modes

ESI has a double-blade shutter. The two blades work together so that when closed one blade or the other is all the way across; i.e. they do not meet in the middle. Sometimes one blade or the other can stick and we need to switch from double-blade mode to single-blade mode. There is a 3 position toggle switch that allows you to choose either single-blade (left), double-blade, or single-blade (right) modes. Getting to this toggle switch is tricky.

Here is a picture that shows the best way to rotate ESI to start.


Preferred starting rotator position for accessing ESI controller
(click to zoom)

ESI has three electronics bays and the covers are difficult to remove and even harder to put back on. With ESI rotated this way and the telescope at horizon the bay you need to get to is on top. You will need a step ladder to work on it, but believe me..........it's best to have the cover horizontal.

The next picture shows the cover off and pushed back a bit. This picture is taken looking over the top of the instrument from behind. Note the two T-handles on the front corners. These are captured and when un-done allow the cover to be lifted up. The rear of the cover (i.e., the end nearest the telescope) fits into a lip. When pulled up and pushed back a bit you will be able to see into the bay.

Note: Before removing the cover, take a moment to note how it looks while attached. Getting this cover back on may be the toughest part of the job. Note: the lid does not look "well attached" even when it is properly in place!


ESI with shutter controller bay cover partially removed
(click to zoom)

The next picture shows the view looking into the front left corner of the bay. The toggle switch you are seeking is on the box labeled EL-1183.


ESI shutter mode toggle switch in controller bay
(click to zoom)

Next is a picture showing (sort of) the toggle switch. Closest to you in the picture is a power cord. Below that, is a fuse. Barely visible below that is the toggle switch. Not visible in this picture, but barely visible once you get your head positioned just right is a label near the toggle switch. It is a capital "L".


Close-up of ESI shutter mode toggle switch
(click to zoom)

The switch moves parallel to the face of the box. The position all the way toward the bottom of the picture is for single blade (left), hence the capital L. The middle position is double blade mode. The position all the way towards the top of the picture is single blade (right).

There is a push button which forces both blades open. It is not visible, in this picture and must be found by feel. It's at the same height as the toggle switch but a bit farther in. In this picture, if you were to remove the power cord you might see it.


Shutter Keyword Description

The relevant keywords for the CCD shutter are:
SHUTTER a read-only boolean keyword that reports either "open" or "not open"
CSHUTTER a read-write keyword used to command the shutter to "open" or "close". If CSHUTTER is displayed using either the show or xshow commands, it reports the last commanded position, not the actual position.
SHUTSTAT a read-only keyword that provides complete information on the 16 possible states of the shutter:
  NORMAL STATES
  "closed L" Right blade is OUT and Left blade is IN.
  "closed R" Left blade is OUT and Right blade is IN.
  "open" indicates that both Left and Right blades are OUT.
This is normal during an exposure.
  "L:in R:err" indicates that Left blade is IN but that right blade is reporting both IN and OUT. However, this is actually the state reported during CCD erase and readout, hence is not necessarily an error.
  ABNORMAL STATES
  "L:err R:err" indicates that Left blade is reporting both IN and OUT and that Right blade is also reporting both IN and OUT
  "L:out R:err" indicates that Left blade is OUT but that right blade is reporting both IN and OUT
  "L:? R:err" indicates that Left blade is neither IN nor OUT (i.e., it is somewhere in between), but that right blade is reporting both IN and OUT
  "L:err R:out" indicates that Left blade is reporting both IN and OUT and Right blade is OUT.
  "L:? R:out" indicates that Left blade is neither IN nor OUT (i.e., it is somewhere in between) and right blade is OUT
  "L:err R:in" indicates that Left blade is reporting both IN and OUT and Right blade is IN.
  "collision!!" Both Left and Right blades are reporting IN
  "L:? R:in" indicates that Left blade is neither IN nor OUT (i.e., it is somewhere in between) and Right blade is IN
  "L:err R:?" indicates that Left blade is reporting both IN and OUT and Right blade is neither in nor OUT (i.e., it is somewhere in between)
  "L:out R:?" Left blade is out and right blade is neither IN nor OUT
  "L:in R:?" Left blade is in and right blade is neither IN nor OUT
  "L:? R:?" Left blade is neither in nor OUT and right blade is neither in nor OUT

Note that the SHUTTER and SHUTSTAT keywords are also displayed in the CCD detail subpanel of the dashboard GUI.

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