E-Detector Motion System

Motion Mechanism

For moving the e-detector to running position or to garage, first open the GUI which can help us do it remotely

• login to cdaql* as cvxwrks
• cd MEDM/compton
• edm -x HLC_E_CompED.edl

The detector can be moved only when the beam is off, hence before any motion on the e-detector is attempted, request MCC to mask Compton electron detector motion FSD. There is no visual verification of this FSD on the motion GUI, so please confirm the masking before moving the detector.

Parking the detector

During standard running conditions, the above GUI at top left shows X = -8.6890. We park it to Garage whenever

1. when we expect beam to be re-established after beam studies or a long downtime.
2. we are sure of not running for a couple of days at a stretch
3. when the beam is intended to be taken straight through (instead of the chicane)

The procedure for parking is:

1. In the drop-down menu-1 (on the left-middle of the e-detector motion GUI), choose 'GO HOME' You should start seeing the box indicating that the detector is moving gets highlighted by yellow.
2. Check to see that the motion is complete. You see the position readback to be X=0.0000 and the yellow highlighting is off.
3. From the same drop-down menu, now select the 'Garage' and the detector start going to Garage.
4. On completion of this motion again, the yellow highlighting goes away and the detector is well parked now.

Putting the detector in standard running position

This should preferably be done by an expert, or if you have been requested to do so by an expert

1. (Check Beam and ...) The detector is probably in Garage, when you start here.
2. You can see two drop-down boxes on the middle left of the GUI. Click on the top drop-down box and select "Go HOME". The detector would start moving towards its predefined HOME position.
3. Once the previously initiated motion is complete (the yellow highlighting turns off), from the same drop-down menu select Go Pos 1. At HOME you can see X=0.0000 on the top left corner of the GUI.
4. The detector again starts moving further towards the beam (apologize for the GUI vertical view being counter-intuitive). The position reader would now show X=-8.289
5. Click on the 2nd drop-down box to select Jog Down 2mm. This would move the detector 2 mm further towards the beam.
6. Once the position starts showing X=-8.489 Repeat the above process again by selecting Jog Down 2mm in the drop-down box.
7. The position reader at top left of the GUI should be showing X=-8.689. YOUR ARE DONE!

Beam can be taken again.

Identifying an unresponsive motion controller: If the e-detector motion GUI shows a red color in "Comm" box. The GUI is possibly frozen.

In this state, an expert should immediately be contacted. The detector GUI may not work without the intervention of Dave Gaskell since this GUI runs on the Moller IOC which is managed by Dave Gaskell. In case the detector gets stuck, then beam can be taken only after ensuring that the detector is out of beam (by physically running 'program 3' locally from the motion controller in the Hall).

General Description

• The electron detector is connected to the QWAD using the custom made [Flex-cable]. The detector is placed inside the vacuum-can whereas the QWAD boards are connected from outside the vacuum-can using appropriate flanges used between the Flex-cable and the QWAD. The connection between e-detector and the QWAD (if the vacuum - can was transparent) can be depicted as in the attached picture.

• The electron detector vacuum - can has a motion mechanism to allow us to move the detector vertically in and out of the beam along with the ability to rotate the detector facing the beam. A schematic view of the assembly can be seen here.

• We are using a stepping motor identified as KML062S04 for vertical motion ( data sheet ) of detector using a MDC accuator ( specifications ). This motor is being controlled by a single axis IDC Controller (User Manual). The Motion Controller can be controlled through its keypad or via computer terminal after installing its software provided on their website

• Motion Controller:
  • Vertically downward motion of the actuator is referred to as 'positive' direction based on the current settings of the controller.
  • All numbers displayed on the controller uses appropriate units of inch and second
  • The Actuator has 3 physically verifiable positions which correspond to a switch on the actuator.
    • EOT+ (end of travel switch in positive direction) will not be used
    • EOT- (end of travel switch in negative direction) used as Garage
    • Home
  • Current Controller Settings:

1. Current: 1.5A
2. Resolution: 18000
3. Inductance: 16 mH
4. Direction: positive
5. Distance Unit: cm
6. Velocity: cm/s
7. Acceleration Unit: cm/s^2
8. Gear Ratio: (GR) = 10:1

Operation

At EOT- (physically top most) the actuator position read back (as seen on the controller display) is

 -3.7833
 00000000      00000000

AC.02 VE.1 DA2 GO

 +2.0000
 00000000      00000000

AC.02 VE.1 DA1 GO

 +1.0000
 00000000      00000000

AC.02 VE.1 DA-2 GO

 -2.0000
 00000000      00000000

AC.02 VE.1 DI1 GO

 -1.0000
 00000000      00000000

Controller Settings

We shall maintain two files for the controller settings

• The most recent settings updated on Nov 29, 2010
• The last working settings updated on Oct 14, 2010

The list of programs loaded in the current configuration are

1. Prog 1: Go Home;
2. Prog 2: 2 cm above chicane beam;
3. Prog 3: Garage, EOT-;
4. Prog 4: 5 mm above chicane beam
5. Prog 10: Incremental motion : -2 mm
6. Prog 11: Incremental motion : -1 mm
7. Prog 12: Incremental motion : +1 mm
8. Prog 13: Incremental motion : +2 mm
9. Prog 14: Incremental motion : -0.5 mm
10. Prog 15: Incremental motion : +0.5 mm
11. Prog 16: Incremental motion : -0.2 mm
12. Prog 17: Incremental motion : +0.2 mm
13. Prog 98: Motor Stopper