1. University of Wisconsin at Madison
DCOPS Readout
James N. Bellinger
University of Wisconsin at Madison
27-February-2007
DCOPS Readout System

2. Overview 60 Lasers 36 Lines 276 DCOPS sensors
(504 combinations of DCOPS and laser)
2 Terminal servers using 16 ports each
Serial readout from each DCOPS
We need to read out the entire profile and fit it

3. Core activities Read and fit the profiles
Store in database for each readout
Fit results
Raw profiles (for offline analysis)
Error information
Store in database for the run or as updated
Configuration: which DCOPS were read out

4. Communications Make errors available to DCS via DimServer
Use Dim commands to control the lasers
Accept control from DCS via DIM commands
HALT: exit program when subprocesses end
ABORT: kill subprocesses and exit program (bug)
RUN: switch from paused to running status
STANDBY: switch from running to paused status
SETDCOPSON: Include selected DCOPS to be read
SETDCOPSOFF: Exclude this DCOPS from readout

5. Comments I assume the default startup state is RUN
The SETDCOPSON and SETDCOPSOFF commands change the readout configuration, and that change will have to be logged.
The current plan is to directly serve only errors and configuration information to DCS.
DCS monitoring gets fits and profiles from the database on as-requested basis, not continuously.

6. Typical “Station” Y Three SLM lines with 10 DCOPS each, and
PT 2
Three SLM lines with
10 DCOPS each, and
6 DCOPS for the
Transfer lines (which
have 12 DCOPS along
the Z direction
PT 3
PT 1 X
PT 4
PT 6
“Radial” SLM DCOPS
“Axial” transfer line DCOPS
PT 5

7. Typical “Station” Y X Terminal Server PT 2 PT 3 PT 1
All the DCOPS in a designated
region are read out on a single
port of the terminal server. This
includes the Transfer Line DCOPS.
Only one process at a time can
communicate with a terminal
server port.
PT 4
PT 6
“Radial” SLM DCOPS
“Axial” transfer line DCOPS
PT 5

8. A different typical “Station”
Terminal Server
PT 2
PT 3
PT 1 X
Different “stations” read out
on different ports. We can
read out different “stations,”
like ME+2 and ME+3, in
parallel.
PT 4
PT 6
“Radial” SLM DCOPS
“Axial” transfer line DCOPS
PT 5

9. Transfer Line issues Y X Terminal Server PT 2 PT 3 PT 1
A Transfer Line uses a DCOPS
from each “station” along the line,
and thus uses a port that an SLM
line also uses.
The readout of Transfer Lines
cannot happen at the same time
as the readout of SLM lines.
PT 4
PT 6
“Radial” SLM DCOPS
“Axial” transfer line DCOPS
PT 5

10. Organization 12 “Stations:”
8 are EndCap with SLMs
4 are central MABS
Read out the 8 EndCap “Stations” in parallel
Have to read out the SLM lines in a “station” in turn, since they use the same ports
To avoid reflections, only one laser on at a time in a “station”
Then read out the 6 Transfer Lines

11. Lowest Level Action
Execute a set of shell commands and read back the results in a pipe: Example
(sleep .2; echo 52TT; sleep .5; echo 52CC; sleep 4; echo 52CG; sleep 5; echo BRK; echo exit) | telnet cmsatsplus.cern.ch 7001
Telnet to terminal server port 1 and
accept the following input commands
Wait briefly for server to catch up
Send command to wake up DCOPS address 52
Wait briefly
Send command to DCOPS to read CCDs
Wait several seconds
Send command to DCOPS to send the background subtracted
profiles
Send terminal server break
Exit the port connection
The output from this
pipe is passed to the
calling routine.

12. Second Level Action
Turn on a laser for an SLM (reply not checked yet!)
Send “group” sample and hold command on both ports
Loop over DCOPS on SLM sending requests for data
Turn off laser, turn on the other, and repeat

13. Third Level Action Loop over SLM's at a “station”
Fork a second level process to read an SLM.
Set a timer and kill the fork if it times out.
Return data in shared memory

14. Fourth Level Action Loop over endcap “stations”
Fork a third level process to read a “station.”
Set a timer and kill the fork if it times out.
As data is returned, interleave fitting with waiting
When all data is fit, return

15. Top Level Action Default is to loop forever over the following:
Call the routine to read all SLMs
Call the routine to read all Transfer Lines
Tag all data with a timestamp and store fits and errors and compressed profiles in Oracle
If standby is requested, sleep and check for change
If halt is requested, exit the program

16. Status
On a 2.4 GHz P4 with local MySQL, a readout cycle in my testbed takes 15 minutes. I believe this is realistic.
Writing profile and error blobs to MySQL works, not tested on Oracle yet
DimService of error bits works
The DIM abort command leaves stray processes around
Configuration for minus side not created yet
Run configuration needs to be read from and written back to Oracle