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* [[POL: Data format and analysis]]
* [[POL: Data format and analysis]]
</div>
</div>
=== Starting the DAQ ===
ssh pol@midpol
start-all
Then go to https://midpol.triumf.ca to see the DAQ webpages.
Data is written to <code>/data1/pol/data/current</code>.
== DAQ machines ==
* midpol - main daq computer, located on ISAC-1 floor behind the BNMR cage
* lxpol - VME controller in the VME rack near midpol
Main account is pol@midpol.


== The POL DAQ System ==
== The POL DAQ System ==
Line 11: Line 27:
The POL experiment has its own [[POL: Hardware and software#Hardware|DAQ
The POL experiment has its own [[POL: Hardware and software#Hardware|DAQ
hardware]] (i.e. VME crate and DAQ modules). These are controlled and
hardware]] (i.e. VME crate and DAQ modules). These are controlled and
read out by a MIDAS [[POL: Hardware and software#Software|frontend]]
read out by a MIDAS [[POL: Hardware and software#Software|frontend]] {{File|name=fepol_32bit.exe}}, which runs on a <b>VMIC VME
{{File|name=fepol_32bit.exe}}. This code runs on a <b>VMIC VME
processor</b> called ''lxpol''.
processor</b> called ''lxpol''.


All the other software runs on the [[POL: Hardware and software#How to switch the Host Computer|host computer]]
All the other software runs on the [[POL: Hardware and software#How to switch the Host Computer|host computer]]
(currently ''isdaq01''). Both ''lxpol'' and ''isdaq01'' run linux.
(currently ''midpol''). Both ''lxpol'' and ''midpol'' run linux.


== Running the POL Experiment ==
== Running the POL Experiment ==
=== Starting the POL Experiment from scratch ===
=== Starting the POL Experiment from scratch ===


* Log on to DAQ host ''isdaq01'' with username ''pol''.
* Log on to DAQ host ''midpol'' with username ''pol''
* In an terminal, type ''start-all''
* In an terminal, type ''start-all''


More details about ''start-all'' is in the [POL: Hardware and software#Scripts|scripts section].
More details about ''start-all'' is in the [[POL: Hardware and software#Scripts|scripts section]].
 
==== The Frontend window for the POL experiment ====
The frontend program runs in a the '''frontend window''' (Figure 1).
 
The frontend window is created (by 
[[#Starting the POL Experiment from scratch|start-all]]) using the
screen manager utility screen, which multiplexes a physical
terminal between several processes. This has the advantage
that  deleting the frontend window (by mistake) will not
kill the frontend program.  Furthermore, the frontend window
can be shown on any terminal, not just the terminal where
''start-all'' was originally run.  


A script ''show-windows'' run on any terminal (logged in as ''pol''
=== Viewing the state of the DAQ programs ===
to isdaq01)  will display the frontend window. An alias
''show-fe'' has been set up to run ''show-windows''.


;Figure 1 Example of the frontend window for the POL experiment
Most interaction with the DAQ is done through the web interface at https://midpol.triumf.ca.
[[Image:Fe_window.png|Figure 1: Example of frontend window for the POL experiment]]


However, you can also view the state of the main DAQ program (called the frontend) by typing ''show-windows'' in a terminal when logged in as pol@midpol. (If connecting to remotely via ssh, you'll need to enable X11 forwarding to see the window - e.g. <code>ssh -Y pol@midpol</code>).


=== Configuring settings/parameters ===


See the documentation about the [[POL:_Webpages#POL_Main_Status_Page|main status page]] for settings that users are expected to edit.


=== Starting a run ===


Click the "Start" button on the [[POL:_Webpages#POL_Main_Status_Page|main status page]], choose whether to write data to disk or not, then confirm that you want to start the run.


=== Shutdown the POL DAQ ===
=== Shutdown the POL DAQ ===


To shutdown the POL DAQ software (i.e. the  MIDAS experiment
To shutdown the POL DAQ software completely:
"pol" )  completely,
 
Log on to isdaq01 with username ''pol'' 
(if not already logged in)
 
In an xterm, type ''kill-all''
 
This will shut down all the clients for the POL experiment,
including mhttpd.
 
 


* Log on to DAQ host ''midpol'' with username ''pol''
* In an terminal, type ''kill-all''


This will shut down all the clients for the POL experiment, including the web server ''mhttpd''.


== Nomenclature ==
== Nomenclature ==
Line 79: Line 76:
;DAC  
;DAC  
<div style="margin-left: 70px;">
<div style="margin-left: 70px;">
The [[POL Experiment DAQ documentation#Galil Rio 47120 DAC/ADC (16 bits)|Galil Rio]] DAC is scanned during the experiment (see [[#DAC scan]]).
The [[POL: Hardware and software#Galil Rio 47120 DAC/ADC (16 bits)|Galil Rio]] DAC is scanned during the experiment (see [[#DAC scan]]).
</div>
</div>
;Dwell Time
;Dwell Time
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<div style="margin-left: 70px;">
<div style="margin-left: 70px;">


*The DAC is controlled by the [[#List of Input Parameters|  input parameters]]:
*Users configure the voltage range and number of increments the DAC should step through. Note that if you specify 10 steps, data will be taken at 11 different voltages. This makes the step size calculation more intuitive (0 to 4V in 10 steps &Implies; 0.4V between data points &Implies; 11 data points as we must include both the lower and upper bounds).
**''DAC start (V)''
**''Number DAC increments''
**''DAC increment (V)''
*At begin-of-run, the DAC is set to the value given by ''DAC Start (V)''.
*At begin-of-run, the DAC is set to the value given by ''DAC Start (V)''.
*After one  [[#supercycle]] (i.e. one or more PPG [[#cycle]]s), the DAC voltage is incremented by the value given by ''DAC increment (V)''
*After one  [[#supercycle]] (i.e. one or more PPG [[#cycle]]s), the DAC voltage is incremented by the value given by ''DAC increment (V)''
Line 102: Line 96:
;Galil RIO
;Galil RIO
<div style="margin-left: 70px;">
<div style="margin-left: 70px;">
DAC/ADC module (see  [[POL Experiment DAQ documentation#Galil Rio 47120 DAC/ADC (16 bits) | Galil Rio]])
DAC/ADC module (see  [[POL: Hardware and software#Galil Rio 47120 DAC/ADC (16 bits) | Galil Rio]])
</div>
</div>
   
   
;Input Parameters
;Input Parameters
<div style="margin-left: 70px;">
<div style="margin-left: 70px;">
The Input Parameters are parameters whose values are input by the user at the beginning of each run. These parameters control the experiment. Click here for  [[#List of Input Parameters]]. The input parameters are available on the [[#Pol Custom page]].   
The Input Parameters are parameters whose values are input by the user at the beginning of each run. These parameters control the experiment. The input parameters are available on the [[POL:_Webpages#Pol Custom page|POL custom page]].   
</div>
</div>
;PPG
;PPG
<div style="margin-left: 70px;">
<div style="margin-left: 70px;">
VME  Pulse programmer module  (see [[POL Experiment DAQ documentation#DAQ Hardware|DAQ Hardware]]). The PPG outputs a pattern of pulses to control the experiment. [[POL Experiment DAQ documentation]]
VME  Pulse programmer module  (see [[POL: Hardware and software#Hardware|DAQ Hardware]]). The PPG outputs a pattern of pulses to control the experiment.
</div>
</div>


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<div style="margin-left: 70px;">
<div style="margin-left: 70px;">
<ul>
<ul>
<li>One [[POL Experiment DAQ documentation#DAQ Hardware|PPG]] Cycle is
<li>One [[POL: Hardware and software#Hardware|PPG]] Cycle is
called a '''cycle'''.
called a '''cycle'''.
</li>
</li>
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</li>
</li>
<li>a hardware signal sent to the  
<li>a hardware signal sent to the  
[[POL Experiment DAQ documentation#Hardware Description|PPG "external trigger" input]]</li>
[[POL: Hardware and software#Hardware|PPG "external trigger" input]]</li>
</ul>
</ul>
<li>A PPG Cycle ends when its program finishes.
<li>A PPG Cycle ends when its program finishes.
<li>The length  of the PPG cycle<span style="color:red; font-weight:bold">*</span>is determined by the [[#List of Input Parameters| input parameters]]
<li>The length  of the PPG cycle<span style="color:red; font-weight:bold">*</span>is determined by the input parameters.
* ''number of time bins'' and  
* ''number of time bins'' and  
* ''dwell time (ms)''
* ''dwell time (ms)''


:<span style="color:red; font-weight:bold">*</span>assuming that the [[#List of Input Parameters| input parameters]]''DAC sleep time (ms)'' and ''TOF pulse width (ms)'', which are also part of the PPG cycle, are set to 0 (i.e. the minimum delay (30ns)).
:<span style="color:red; font-weight:bold">*</span>assuming that the input parameters ''DAC sleep time (ms)'' and ''TOF pulse width (ms)'', which are also part of the PPG cycle, are set to 0 (i.e. the minimum delay (30ns)).
</li>
</li>
</ul>
</ul>
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<ul>
<ul>
<li>A run starts when the user starts the DAQ system (by
<li>A run starts when the user starts the DAQ system (by
pressing <span style="color: #444444; background-color: #CCCCCC; font-style:italic; font-size: 90; padding:0.25em;padding-left: 0.5em;padding-right: 0.5em;border:1px solid #808080;border-radius: 5px;margin-bottom:1px;">Start</span>on the [[#POL Main Status Page]] or   
pressing <span style="color: #444444; background-color: #CCCCCC; font-style:italic; font-size: 90; padding:0.25em;padding-left: 0.5em;padding-right: 0.5em;border:1px solid #808080;border-radius: 5px;margin-bottom:1px;">Start</span>on the [[POL:_Webpages#POL Main Status Page|main status page]] or   
[[#Pol Custom page]])</li>
[[POL:_Webpages#Pol Custom page|Pol custom page]])</li>
<li>A run ends </li>
<li>A run ends </li>
<ul>
<ul>
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;SIS3820 Scaler/MCS  
;SIS3820 Scaler/MCS  
<div style="margin-left: 70px;">
<div style="margin-left: 70px;">
VME multichannel scaler module  (see [[POL Experiment DAQ documentation#Hardware| DAQ Hardware]]).
VME multichannel scaler module  (see [[POL:_Hardware_and_software#Hardware| DAQ Hardware]]).
</div>
</div>
;Supercycle
;Supercycle
Line 165: Line 159:
<ul>
<ul>
<li>One or more [[#ppg cycles]] at the  '''same''' DAC voltage is called one '''supercycle'''</li>
<li>One or more [[#ppg cycles]] at the  '''same''' DAC voltage is called one '''supercycle'''</li>
<li>The number of ppg cycles per supercycle is determined  by the  [[#List of Input Parameters|input parameter]] ''Num PPG cycles per DAC increment''</li>
<li>The number of ppg cycles per supercycle is determined  by the  input parameter ''Num PPG cycles per DAC increment''</li>
<li>  If the DAC is incremented after  each PPG cycle i.e. ''Num PPG cycles per DAC increment'' = 1, '''cycle and supercycle are identical'''</li>
<li>  If the DAC is incremented after  each PPG cycle i.e. ''Num PPG cycles per DAC increment'' = 1, '''cycle and supercycle are identical'''</li>
</ul>
</ul>
<ul>
<ul>
<li>The time bin data from each cycle within one supercycle is summed. </li>
<li>The time bin data from each cycle within one supercycle is summed. </li>
<li>At the end of each supercycle, the scaler data are output (as [[vmicbanks.html|MIDAS Banks]]) and the DAC is incremented.</li>
<li>At the end of each supercycle, the scaler data are output (as [[POL:_Data_format_and_analysis|MIDAS Banks]]) and the DAC is incremented.</li>
</ul>
</ul>
</div>  
</div>  
Line 178: Line 172:
<div style="margin-left: 70px;">
<div style="margin-left: 70px;">
The time during the  [[#scaler]] is enabled to collect data is divided into a   
The time during the  [[#scaler]] is enabled to collect data is divided into a   
number of time bins, each of  length given by the  dwell time. Both of these values are [[#List of Input Parameters|input parameters]] used to program the PPG.  The scaler advances to the next time bin when it receives the LNE signal from the PPG (see  [[POL Experiment DAQ documentation#Hardware" | Hardware]]).  
number of time bins, each of  length given by the  dwell time. Both of these values are input parameters used to program the PPG.  The scaler advances to the next time bin when it receives the LNE signal from the PPG (see  [[POL:_Hardware_and_software#Hardware" | Hardware]]).  
</div>   
</div>   


Line 184: Line 178:


== Troubleshooting ==
== Troubleshooting ==
=== General advice ===
<ol>
<li>See if there's an obvious error message on the "Messages" webpage</li>
<li>Try restarting the DAQ programs</li>
<li>Try power-cycling the VME crate</li>
</ol>


=== The run would not start ===
=== The run would not start ===
Check the Error/Information message log for more information. Reasons for the run not starting include :
Check the "Messages" webpage for more information. Reasons for the run not starting include :
<ul>
<ul>
<li>frontend code is not running</li>
<li>frontend code is not running</li>
<li>error in frontend parameter values</li>
<li>error in frontend parameter values</li>
<li>VME crate powered down
<li>hardware not responding properly</li>
</li>
</ul>
</ul>


=== The run stopped unexpectedly ===
=== The run stopped unexpectedly ===
Check the Error/Information message
Check the "Messages" webpage for more information. Reasons for the run stopping include:
log for more information. Reasons for the run stopping unexpectedly include:
<ul>
<ul>
<li>Run reached number of scans requested (input parameter ''number of scans'' is non-zero)</li>
<li>Run reached number of scans requested (input parameter ''Stop after N loops'' is non-zero)</li>
<li>DAC value did not change after increment</li>
<li>The frontend code detected a fatal error - see message log and frontend xterm</li>
<li>The frontend code detected a fatal error - see message log and frontend xterm</li>
</ul>
</ul>


=== DAC Scan stops with error; cannot step the DAC successfully ===
If the "Messages" webpage shows errors of the form:
<pre>
Scaler is showing 2948 bins at start of cycle rather than expected 0
Data source Histos isn't ready for the start of the next cycle!
</pre>
then the scalers are either configured incorrectly, or are not behaving as expected. You will likely need to use the <code>sis3820_interactive_32bit.exe</code> debugging program on lxpol to view the registers on the scaler and ensure they are as expected (especially the LNE prescale setting and whether it's in arm or enable mode). If the scaler settings look okay, there may be a programming error in the DAQ.


The following refers to check parameters in the [[#Information Table]] i.e. ''DAC check'', ''jitter'': 
=== Run starts, but scan does not progress ===
 
Check the stdout of the frontend program for repeating lines like "Scaler has seen 0/10100 bins".
;Note:
:''DAC check'' should now be disabled in order to run with small DAC increments. ''DAC check'' should only be enabled for testing.
 
If running with ''DAC check'' enabled, check the following parameters in the [[#Information Table]]: 
* check jitter parameter is reasonable (i.e.  &gt;=  [[POL Experiment DAQ documentation##Stepping the DAC| DAC LSB]]) .
 
* If  DAC_increment is very small (i.e. close to LSB or jitter), you will have to run with  ''DAC check'' disabled (i.e. no  [[POL Experiment DAQ documentation#Stepping the DAC" | checks on DAC stepping ]]).
 
=== Run starts but DAC not scanning, no data ===
 
The frontend code is probably not running, and the [[#Alarm_System" | alarm system]] disabled.
If the alarm system is enabled, the run will be prevented from starting, and an alarm banner
will appear to indicate the problem.
 
Otherwise, check that the hardware (Galil Rio, Power supply etc.) is all switched on and
working.  The PPG relies on an external signal from the TOF
to start the next cycle. If this signal is not present, the PPG will run one cycle then stop, waiting for an external start.
 
For testing, can switch PPG external start to internal (under Frontend Flags on the Custom Page) . The PPG should then continue past the first cycle. In this case, investigate connection of End TOF Signal to PPG External Start.


<ul>
<li>If the scaler has seen 0 or -1 bins, check the cabling between the PPG and the scaler, as the PPG probably never started</li>
<li>If scaler has seen 100 bins (or however many time bins you specified for the "Num time bins" setting) and you're using pulsed beam mode, check the cabling between the RFQ and the PPG</li>
<li>If the scaler has seen 10099/10100 bins (or one less than the expected number), there is either a programming error in the DAQ or the scaler has been manually configured incorrectly (it is likely configured for "arm" logic rather than "enable" logic). Try restarting the frontend.</li>
</ul>


=== Alarm banner is present ===
=== Alarm banner is present ===
Line 245: Line 234:


<pre>
<pre>
pol@isdaq01 pol]$ ssh lxpol
[pol@midpol pol]$ ssh lxpol
Last login: Wed Apr  2 16:05:12 2014 from isdaq01.triumf.ca
[pol@lxpol ~]$ bash
 
(new daq) [pol@lxpol ~]$ pol_new/packages/pol/bin/fepol_32bit.exe
[pol@lxpol ~]$ online/pol/pol_fevme.exe
</pre>
</pre>


Line 266: Line 254:
;NOTE
;NOTE
: If you cannot ssh to lxpol, check that the VME crate is powered up and the network is working.
: If you cannot ssh to lxpol, check that the VME crate is powered up and the network is working.


=== How to switch the Host Computer ===
=== How to switch the Host Computer ===
The host computer is the desktop computer that users of the ''pol'' experiment
The host computer is the desktop computer that users of the ''pol'' experiment
log into to run the DAQ. Currently it is '''isdaq01'''.  If isdaq01 dies, the experiment can
log into to run the DAQ. Currently it is '''midpol'''.  If midpol dies, the experiment can
be switched to run on an alternate host that is part of the isdaq00 NIS cluster, e.g. isdaq06.
be switched to run on an alternate host that is part of the isdaq00 NIS cluster, e.g. isdaq06.
The alternate machine also has access to the  {{Filepath|path=/home/pol}} directory.
The alternate machine also has access to the  {{Filepath|path=/home/pol}} directory.


<ul>
* If the current host computer (midpol) is still running, type ''kill-all'' and log out.
<li>If the current host computer (isdaq01) is still running,
* Log onto the alternate host computer (isdaq06)
type ''kill-all'' and log out.</li>
** Edit the definition of <code>$DAQ_HOST</code> in /home/pol/.bashrc
</ul>
** Edit the SHM host file <code>/home/pol/online/.SHM_HOST.TXT</code>
<ul>
** Log out and log in again
<li>Log onto the alternate host computer (isdaq06)
** Check environment variable DAQ_HOST is now set to isdaq06  
</li>
** Execute  ''start-all'' and point the webserver to ''isdaq06:8088''
<li>Now edit /home/pol/.cshrc as follows:</li>
<ul>
<li>Find the lines </li>
<pre style="margin-left: 40px;"> Edit to change the DAQ_HOST environment variable to the alternate host, i.e.
# The MIDAS experiment (pol) is running on $DAQ_HOST
setenv DAQ_HOST isdaq01
#setenv DAQ_HOST isdaq06  ## alternative host
</pre>
<div style="margin-left: 40px;" > Edit to change the DAQ_HOST environment variable to the alternate host, i.e.
 
<pre style="margin-left: 40px;># The MIDAS experiment (pol) is running on $DAQ_HOST
#setenv DAQ_HOST isdaq01
setenv DAQ_HOST isdaq06  ## alternative host
</pre>
</div>
 
<ul>
<li>Remove the SHM host file :
</li>
</ul>
<pre style="margin-left: 40px;" >
[pol@isdaq06 ~] $ rm /home/pol/online/pol/.SHM_HOST.TXT
</pre>
<ul>
<li>Log out and log in again</li>
<li>Check environment variable DAQ_HOST is now set to isdaq06
</li>
</ul>
<pre style="margin-left: 40px;">
[pol@isdaq06 ~] $ printenv | grep DAQ_HOST
DAQ_HOST=isdaq06
</pre>
<ul>
<li>Execute  ''start-all'' and point the webserver to ''isdaq06:8088''</li>
</ul>
 
 


== POL DAQ updates ==
== POL DAQ updates ==
* February 2023 DAQ Host is now midpol
* January 2022 Rewritten using the cycling framework
* January 2022 Rewritten using the cycling framework
* April 2016 DAQ Host is now isdaq01
* April 2016 DAQ Host is now isdaq01

Latest revision as of 13:51, 17 February 2023

Links

Starting the DAQ

ssh pol@midpol
start-all

Then go to https://midpol.triumf.ca to see the DAQ webpages.

Data is written to /data1/pol/data/current.

DAQ machines

  • midpol - main daq computer, located on ISAC-1 floor behind the BNMR cage
  • lxpol - VME controller in the VME rack near midpol

Main account is pol@midpol.

The POL DAQ System

The DAQ system for the POL experiment uses MIDAS, the standard DAQ system at TRIUMF.

The POL experiment has its own DAQ hardware (i.e. VME crate and DAQ modules). These are controlled and read out by a MIDAS frontend fepol_32bit.exe, which runs on a VMIC VME processor called lxpol.

All the other software runs on the host computer (currently midpol). Both lxpol and midpol run linux.

Running the POL Experiment

Starting the POL Experiment from scratch

  • Log on to DAQ host midpol with username pol
  • In an terminal, type start-all

More details about start-all is in the scripts section.

Viewing the state of the DAQ programs

Most interaction with the DAQ is done through the web interface at https://midpol.triumf.ca.

However, you can also view the state of the main DAQ program (called the frontend) by typing show-windows in a terminal when logged in as pol@midpol. (If connecting to remotely via ssh, you'll need to enable X11 forwarding to see the window - e.g. ssh -Y pol@midpol).

Configuring settings/parameters

See the documentation about the main status page for settings that users are expected to edit.

Starting a run

Click the "Start" button on the main status page, choose whether to write data to disk or not, then confirm that you want to start the run.

Shutdown the POL DAQ

To shutdown the POL DAQ software completely:

  • Log on to DAQ host midpol with username pol
  • In an terminal, type kill-all

This will shut down all the clients for the POL experiment, including the web server mhttpd.

Nomenclature

Bin

see #time bin

Cycle

see #PPG Cycle

DAC

The Galil Rio DAC is scanned during the experiment (see #DAC scan).

Dwell Time

The Dwell Time is the same as the Bin Width. This is the time the Scaler collects the data for each #time bin.

DAC Scan (or Sweep)
  • Users configure the voltage range and number of increments the DAC should step through. Note that if you specify 10 steps, data will be taken at 11 different voltages. This makes the step size calculation more intuitive (0 to 4V in 10 steps ⇒ 0.4V between data points ⇒ 11 data points as we must include both the lower and upper bounds).
  • At begin-of-run, the DAC is set to the value given by DAC Start (V).
  • After one #supercycle (i.e. one or more PPG #cycles), the DAC voltage is incremented by the value given by DAC increment (V)
  • When the requested number of Number of DAC increments are done, one DAC scan has been completed.
  • A number of DAC scans is usually done during each #run.
Galil RIO

DAC/ADC module (see Galil Rio)

Input Parameters

The Input Parameters are parameters whose values are input by the user at the beginning of each run. These parameters control the experiment. The input parameters are available on the POL custom page.

PPG

VME Pulse programmer module (see DAQ Hardware). The PPG outputs a pattern of pulses to control the experiment.


PPG Cycle
  • One PPG Cycle is called a cycle.
  • A PPG Cycle starts when the PPG receives a "start" signal by
  • A PPG Cycle ends when its program finishes.
  • The length of the PPG cycle*is determined by the input parameters.
    • number of time bins and
    • dwell time (ms)
    *assuming that the input parameters DAC sleep time (ms) and TOF pulse width (ms), which are also part of the PPG cycle, are set to 0 (i.e. the minimum delay (30ns)).
Run
  • A run starts when the user starts the DAQ system (by pressing Starton the main status page or Pol custom page)
  • A run ends
    • when the user stops the DAQ system (by pressing Stop on the main status or custom page) or
    • automatically if an error is detected
SIS3820 Scaler/MCS

VME multichannel scaler module (see DAQ Hardware).

Supercycle
  • One or more #ppg cycles at the same DAC voltage is called one supercycle
  • The number of ppg cycles per supercycle is determined by the input parameter Num PPG cycles per DAC increment
  • If the DAC is incremented after each PPG cycle i.e. Num PPG cycles per DAC increment = 1, cycle and supercycle are identical
  • The time bin data from each cycle within one supercycle is summed.
  • At the end of each supercycle, the scaler data are output (as MIDAS Banks) and the DAC is incremented.
Time Bin

The time during the #scaler is enabled to collect data is divided into a number of time bins, each of length given by the dwell time. Both of these values are input parameters used to program the PPG. The scaler advances to the next time bin when it receives the LNE signal from the PPG (see Hardware).


Troubleshooting

General advice

  1. See if there's an obvious error message on the "Messages" webpage
  2. Try restarting the DAQ programs
  3. Try power-cycling the VME crate

The run would not start

Check the "Messages" webpage for more information. Reasons for the run not starting include :

  • frontend code is not running
  • error in frontend parameter values
  • hardware not responding properly

The run stopped unexpectedly

Check the "Messages" webpage for more information. Reasons for the run stopping include:

  • Run reached number of scans requested (input parameter Stop after N loops is non-zero)
  • The frontend code detected a fatal error - see message log and frontend xterm

If the "Messages" webpage shows errors of the form: 

Scaler is showing 2948 bins at start of cycle rather than expected 0
Data source Histos isn't ready for the start of the next cycle!

then the scalers are either configured incorrectly, or are not behaving as expected. You will likely need to use the sis3820_interactive_32bit.exe debugging program on lxpol to view the registers on the scaler and ensure they are as expected (especially the LNE prescale setting and whether it's in arm or enable mode). If the scaler settings look okay, there may be a programming error in the DAQ.

Run starts, but scan does not progress

Check the stdout of the frontend program for repeating lines like "Scaler has seen 0/10100 bins".

  • If the scaler has seen 0 or -1 bins, check the cabling between the PPG and the scaler, as the PPG probably never started
  • If scaler has seen 100 bins (or however many time bins you specified for the "Num time bins" setting) and you're using pulsed beam mode, check the cabling between the RFQ and the PPG
  • If the scaler has seen 10099/10100 bins (or one less than the expected number), there is either a programming error in the DAQ or the scaler has been manually configured incorrectly (it is likely configured for "arm" logic rather than "enable" logic). Try restarting the frontend.

Alarm banner is present

This indicates an error that may prevent the run from starting. Fix the problem and clear the alarm.

Frontend code will not run - frontend window disappears immediately

This means that the frontend code has detected an error, and exits. Check for Error Messages. If necessary, start the frontend code in an xterm to get more information, because the window will not disappear on failure.

This error will occur if there is a problem with the VME Crate (e.g. powered down), frontend program not running, Galil Rio DAC/ADC not responding etc.

How to Start frontend code in an xterm

Log onto the VMIC device lxpol, e.g. from an xterm on the host or local computer, and start the frontend code, e.g. 

[pol@midpol pol]$ ssh lxpol
[pol@lxpol ~]$ bash
(new daq) [pol@lxpol ~]$ pol_new/packages/pol/bin/fepol_32bit.exe

The frontend will run and go through its initialization procedure.

It may detect an error, e.g. 

Connecting to Galil device at IP 192.168.1.100
terminate called after throwing an instance of 'KOsocketException'
Abort

In this case, there is a hardware problem with the Galil Rio DAC and the frontend code is aborted. Check that the Galil Rio DAC is present, powered up and connected to the VMIC via a network connection.

NOTE
If you cannot ssh to lxpol, check that the VME crate is powered up and the network is working.

How to switch the Host Computer

The host computer is the desktop computer that users of the pol experiment log into to run the DAQ. Currently it is midpol. If midpol dies, the experiment can be switched to run on an alternate host that is part of the isdaq00 NIS cluster, e.g. isdaq06. The alternate machine also has access to the /home/pol directory.

  • If the current host computer (midpol) is still running, type kill-all and log out.
  • Log onto the alternate host computer (isdaq06)
    • Edit the definition of $DAQ_HOST in /home/pol/.bashrc
    • Edit the SHM host file /home/pol/online/.SHM_HOST.TXT
    • Log out and log in again
    • Check environment variable DAQ_HOST is now set to isdaq06
    • Execute start-all and point the webserver to isdaq06:8088

POL DAQ updates

  • February 2023 DAQ Host is now midpol
  • January 2022 Rewritten using the cycling framework
  • April 2016 DAQ Host is now isdaq01
  • May 2015 frontend window now created using screen utility
  • July 2014 Galil Rio loaded with internal program (by Donald) to average ADC0-3 values. Averaged values are sent to banks CYCL.
  • May 2014 DAQ frontend code partially rewritten to reduce dead time.
  • April 2014 Galil Rio DAC/ADC replaces GPIB DAC . DAQ host is now isdaq06.
  • 2013 GPIB DAC controlled directly from isdaq01 rather than midtis07
  • April 2011 VMIC- based system for POL (replaces PPC-based system shared with BNQR expt). Pol's new scaler isthe VME scaler (SIS3820)
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