# Quick Check List

April 2003

Why not read the Data Acquisition at ANU user guide? If you just cannot manage that at least read these selections.

# 1 Important changes April 2003

## 1.1 Data format

The raw data received from the MEGHA electronics via the f2vb is processed in the data acquisition processor (vme1) and reformatted using the standard MIDAS data format (see http://npg.dl.ac.uk/documents/edoc073/edoc073.html) before writing to tape. Sunsort now has a data format MIDAS which can handle this data. You should now find that Sunsort reports zero errors when processing this data.

## 1.2 Data transfer

The method of sending data from the data acquisition processor (vme1) to the tape server has been changed to use a TCP network connection which allows much higher data rates. In online mode (data source = REMOTE) Sunsort must run in the same workstation as the tape server (charissa1).

## 1.3 Network at ANU

All the Charissa equipment at ANU is now connected to a secure network and accesses the Internet via a firewall. This should make no difference to outgoing connections but incoming connections are restricted by the firewall to a limited set of permitted connections. See the network connection section in the Charissa Computers at ANU document.

# 2 Running Sunsort (on-line)

Login to charissa1 and start Sunsort in the usual way. Select format MIDAS (not megha) and select sort media Remote.

In order to run Sunsort in online mode data must be transferred from the data acquisition system (vme1) to the tape server which must be in the GO state.

To get data for Sunsort – start the experiment writing to tape OR if tape output is not required then while in STOP state go to the Tape Control window and select No Storage. Then GO.

Remember to disable No Storage when you are ready to write data to tape.

# 3 F2VB

A useful diagnostic is started by the F2VB menu item in the Diagnostics menu This enables you to spy on the buffer RAM of the F2VB module and see your raw data. Very useful when the electronics is not working to its normal efficiency.

Ensure the option button shows display data RAM and click on the read button. 64 32 bit words of the data RAM are displayed. You can set the start address offset or enable the increment RAM address checkbox to step through the data RAM.

A useful button is Dump using current addresses which reads the data ram at the buffer address currently being written. [be careful if the data rate is VERY slow or stopped as the dump may show old data]

The format data RAM button will generate a formatted display of the last block of the data RAM displayed using the selected format option (make sure this is correct for your hardware but the default is for MEGHA electronics). Look for excessive amounts of bad data which would suggest that your electronics needs attention.

No data? - Check that you have beam!! Check that you are GOING!! If you are sure check the F2VB state.

Check that event storage active is enabled (ticked)

If not – check that you really are Going

If it is then

If List ended and Memory full are not on permanently (ticked) [use redisplay to update] and FIFO empty is ticked then the electronics is not sending data to the f2vb

If it is and List ended is set permanently and FIFO empty is not ticked then you may have a data acquisition system problem.

# 4 Histogramming

At the present time the system cannot create all 640 8K channel histograms required and so all options are equivalent to None. However 2 histograms (Stat & Rate) are created which show the activity on a data item basis.

Megha crate 1 increments into channels 64 -> 127; Megha crate 2 increments into channels 128 -> 191 etc.

Within a crate block the order is Ch0 E, Ch0 T, Ch1 E etc.

The Rate histogram shows the increment rate / sec for the Stat histogram and so is a very useful check on the adcs.

# 5 Megha amplifiers

To obtain a printout of the amplifier settings for your run book. Select Act on Crates? All; click on Show Settings and then use Ctrl+P to print the contents of the window containing the settings display.

# 6 Statistics

Useful data quality statistics are available by selecting the Statistics menu item from the Monitoring menu on the Experiment Control window. If the ratio of data word skipped to total data words or the ratio of events not acceptable to events is high then the electronics should be checked. It may be useful to use the f2vb diagnostic option.

Total data words number of data words (16 bit) read from the f2vb

Events number of good events found

Event not acceptable total number of events which contain some type of serious error and are discarded

Bad flag bits a data word which is not a end of block or event header in which the label part flag bits are not 001 and the data part flag bits are not 100 [ie data word is not 0x2xxx8xxx]

Missing start token all data words received when a start event token is expected

Missing stop token all data words discarded when the end of data buffer is reached but there is a current partial event.

Data after stop token all data words discarded when the end of block token is received but there is still data in the data buffer

Data word skipped a count of the total number of data words discarded for any of the reasons given. This can be compared with the Total data words received.