Wiki > The Backend System > Specific Device IOC > Miscellaneous motion control > Reflectometry IOC > POLREF

Specific information about POLREF.

Axes when sample is in horizontal configuration.

In vertical configuration CHI and Theta/PHI/ANGLE are swapped, as are x and y axes. NB slit directions are not so in vertical mode the collimation is controlled by the horizontal slits.

Below is an overview to explain which terms relate to each other in horizontal/vertical mode (differences highlighted):

Slit 2

Horizontal Mode

Block	Parameter Name	Change Axis in REFL	Motor	Motor Name	General term	Other
S2OFFSET	S2OFFSET	POSITION	0402	Slit 2 Z	Slit 2 Height	-
S2ANGLE	S2ANGLE	ANGLE	0605	Slit 2 Tilt	Slit 2 Tilt	-

Vertical Mode

Block	Parameter Name	Change Axis in REFL	Motor	Motor Name	General term	Other
S2OFFSET	S2OFFSET	POSITION	0305 / 0306	Slit 2 East / West	Slit 2 Horizontal	Using HCENT as Offset
S2CHI	S2CHI	CHI	0605	Slit 2 Tilt	Slit 2 Tilt	-

Frame Overlap Mirror (FOM)

Horizontal Mode

Block	Parameter Name	Change Axis in REFL	Motor	Motor Name	General term	Other
FTHETA	FTHETA	ANGLE	0205	FOM Theta	FOM Theta	-
FCHI	FCHI	PSI	0206	FOM Chi	FOM Psi	-
FOFFSET	FOFFSET	POSITION	0208	FOM Z	FOM Height	-
FTRANS	FTRANS	TRANS	0207	FOM Y	FOM Trans	-

Vertical Mode

Block	Parameter Name	Change Axis in REFL	Motor	Motor Name	General term	Other
FTHETA	FTHETA	ANGLE	0205	FOM Theta	FOM Theta	-2.3 correction
FCHI	FCHI	PSI	0206	FOM Chi	FOM Psi	+90.0 correction
FOFFSET	FOFFSET	POSITION	0207	FOM Y	FOM Trans	-
FTRANS	FTRANS	TRANS	0208	FOM Z	FOM Height	-

Polarizing Mirror

Horizontal Mode

Block	Parameter Name	Change Axis in REFL	Motor	Motor Name	General term	Other
SMANGLE	SMANGLE	ANGLE	0301	Polarizer THETA	Polarizer Theta	-
SMCHI	SMCHI	PSI	0302	Polarizer CHI	Polarizer Psi	-
SMOFFSET	SMOFFSET	POSITION	0304	Polarizer Z	Polarizer Height	-
SMTRANS	SMTRANS	TRANS	0303	Polarizer Y	Polarizer Trans	-

Vertical Mode

(Polarizer not currently used in vertical mode - NR only)

Block	Parameter Name	Change Axis in REFL	Motor	Motor Name	General term	Other
SMANGLE	SMANGLE	ANGLE	0301	Polarizer THETA	Polarizer Theta	-2.3 correction
SMCHI	SMCHI	PSI	0302	Polarizer CHI	Polarizer Psi	+90.0 correction
SMOFFSET	SMOFFSET	POSITION	0303	Polarizer Y	Polarizer Trans	Park position correction
SMTRANS	SMTRANS	TRANS	0304	Polarizer Z	Polarizer Height	-

Sample Stack

Horizontal Mode

Block	Change Axis in REFL	Parameter Name	Motor	Motor Name	General term
Height	POSITION	SAMPOFFSET	0403	SS Low Z	Coarse Height
Height2	HEIGHT	SAMPHEIGHT	0404	SS High Z	Fine Height
Sample_Changer	-	-	1001	Sample Changer	Sample Changer
Trans	TRANS	TRANS	0405	SS Horizontal	Trans
PHI	ANGLE	PHI	0407	SS Lower Gonio	Phi
PSI	PSI	PSI	0406	SS Upper Gonio	Psi
CHI	CHI	CHI	0408	SS Rotation	Chi

Vertical mode:

Block	Change Axis in REFL	Parameter Name	Motor	Motor Name	General term
Height	POSITION	SAMPOFFSET	0405	SS Horizontal	Trans
Height2	-	-	-	-	-
Sample_Changer	-	-	-	-	-
Trans	TRANS	TRANS	0403	SS Low Z	Coarse Height
PHI	ANGLE	PHI	0408	SS Rotation	Chi
PSI	PSI	PSI	0406	SS Upper Gonio	Psi
CHI	CHI	CHI	0407	SS Lower Gonio	Phi

Bench

Horizontal mode:

Block	Change Axis in REFL	Parameter Name	Motor	Motor Name	General term
BENCHOFFSET	POSITION	BENCHOFFSET	0801 / 0802	Bench Front Z/ Bench Rear Z	Bench Height
BENCHANGLE	ANGLE	BENCHANGLE	0801 / 0802	Bench Front Z/ Bench Rear Z	Bench Angle
BENCHSEESAW	SEESAW	BENCHSEESAW	0801 / 0802	Bench Front Z/ Bench Rear Z	Bench Seesaw
BENCHCHI	CHI	BENCHCHI	0804	Bench Arc	Bench Chi

Vertical mode:

Block	Change Axis in REFL	Parameter Name	Motor	Motor Name	General term
BENCHTRANS	TRANS	BENCHTRANS	0801 / 0802	Bench Front Z/ Bench Rear Z	Bench Height
BENCHCHI	CHI	BENCHCHI	0801 / 0802	Bench Front Z/ Bench Rear Z	Bench Angle
BENCHSEESAW	SEESAW	BENCHSEESAW	0801 / 0802	Bench Front Z/ Bench Rear Z	Bench Seesaw
BENCHANGLE	ANGLE	BENCHANGLE	0804	Bench Arc	Bench Chi

Slit 3 is a tall set of normal jaws sitting on the bench. In horizontal sample mode the centre of the jaws is set using the S3OFFSET parameter which sets the distance from beam to the jaws, (usually set to 0). The bench movement means that the centre of the jaws rarely needs to change except during a slit scan. Slit 3 can also be set into beam blocker mode; south jaw in horizontal mode, east or west jaws in vertical sample mode. In this state the beam blocked jaws will move independently of the slit centre using S3S and S3N or S3W and S3W. They retain the natural jaw directions so that positive is away from the centre of the jaw.

Components that are on the bench do not track the beam in the same way as normal components. They rely on the underlying bench to track the beam and then their positions are just relative to the bench. This will in effect look the same as if they were tracking the beam but they don't.

Blocks that may be confusing:

• Height: Distance between the beam and the centre of rotation; usually set a 0. This moves the course z stage tracking the beam.
• Height2: Distance from the sample centre of rotation to the sample. This is used to align the sample with the beam.

It is hard to know which parameters to autosave and which not to. Probably with use we will find out. I have gone with Theta and polariser angles are not autosaved all other heights and offsets are. So that when coming back from SECI the setpoints will mirror those in SECI quite closely. Other axis parameters, direct parameters and slits are not autosaved so they come back as they are, except for bench angle offset and seesaw which are autosaved.

Testing results are here.

Issues were:

1. On running the routine for transferring the SECI motor setups to IBEX, all the encoders were turned off. This may be a one off thing but still it should happen.
   • This was because I ran the original motor setup in sim mode. Yes this should not happen, I have added it to the information page so it won’t happen again.
2. There was a request for a command in python for interrogating a motor e.g pos Phi and it tells you all sorts of things about phi like its position offset limits etc. that could then be used in a script.
   • We will probably never get to this if we put it on our list. I will send some details describing how you might create such a script let me know if you need help.
3. There again also seemed to be an issue with High and low limits being the wrong way around as well as directions not being correct after the transfer.
   • For all axes on the spreadsheet I have confirmed that they are wrong in SECI; there is nothing we can do about this.
4. Where Dual position was marked in the SECI motor table there were issues of odd behaviour in IBEX that will need fixing. This affects the PolREF current sheet.
   • Ticket 5647
5. The major issue was that the IBEX setpoints were not transferred back to SECI when switching form IBEX back to SECI. The current positions were. This means that if someone reboots SECI and then presses move then the beamline will move unexpectedly. This is not good and needs a fix of some kind as it could lead to crash’s I know future wise we should all be in IBEX but for the next year I can see people switching back and forth,
   • I think that a script the user can run in OpenGenie is probably the best idea so that they have control over when they want they readbacks to be the same as the setpoint. Please read and approve 5648.
6. Labels that were the wrong way around such as the laser Gimbal axes theta and chi. We swapped them but not necessarily in the config, Also for some reason the PolREF sample stage had phi and Psi the wrong way around and again I am not sure they were swapped to the correct position fully.
   • Gimbal is wrong in SECI
   • PSI and CHI was my mistake in the config the motors are gonio upper and lower and I guessed the wrong way round. Now fixed in config.
7. Stop_ibex_server_start_seci does not finish. It starts seci but waits for SECI to finish, which is not what we want. Make it start in separate console.
   • #5651
8. There was an error loading programs into SECI this has been fixed by combining programs in the galil.
9. There is something wrong with the bench movement. We think that it is because it was not synced and the max bench angle had not been implemented. (Extra note we tried moving the bench but had problems so we then set the motion of the slide to not be synchronised, then reversed the slide but we never set synchronised on the movement again)
   • We should retest this after completing #5541
10. Jaw 1 was synchronised and should not be (jaws in general are not synchronised to avoid clashing).
    • Changed in config
11. Some errors in the logs for which I have created tickets
    • #5649
    • #5650
12. Height and Height2 point at the same thing on the OPI
    • Corrected in master
13. Check backlash on slits is ok, currently move is towards centre of slit them slowly out to position.