Links

Purpose

The purpose of the mhttpd Sequencer Web Page to provide a visual display for the Sequencer. Using the Sequencer Page, Sequencer scripts can be loaded, edited and run.

Access to the Sequencer Page

The Sequencer Page is displayed by clicking on Sequencer button on the mhttpd Status Page or other mhttpd web page.

Note: If the Sequencer button is not present on the Status Page, it may have been suppressed.

Features of the Sequencer Page

The Sequencer Page takes its parameters from the /Sequencer ODB tree. Sequencer scripts can be loaded and run from the Sequencer Page. A visual editor is provided to edit scripts. A display is provided showing the progress of a running script, and the last few Midas messages are also shown (Figure 5). If Edit-on-Sequence Parameters are defined, these will be displayed when a sequence is started.

How to input and run a Sequencer Script

A Sequencer Script is written using commands recognized by the Sequencer. See Sequencer Commands for the list of sequencer commands.

Load a Sequencer Script

Press Sequencer on Status Page. The first time the button is pressed, the Sequencer Page will appear as in Figure 1, where no load file has been specified.
Either

Press Edit Script and input a new test sequence
i.e. type in Sequencer Commands or paste in an example file (e.g. #Sequence file or one of MSL Example file or MSL Example file ) as in Figure 2.
save the script by pressing Save. You will be asked for a file name.

Or

load an existing sequencer scriptfile using Load Script as in Figure 3.

Note: The directory path where the sequencer files will be saved is set by the ODB parameter /Sequencer/State/Path.

Table 1
Figure 1: Initial Sequencer page	Figure 2: Display and/or Edit a Sequencer script	Figure 3: Select a Sequencer file

Figure 4: Select a Sequencer file

Start a Sequencer Script

After a sequencer script has been |loaded, start the script:

Press Start Script button to start the script.

You will be asked to input any required parameters as in Figure 4 (in this case the number of runs, see test_seq.msl).
If Edit-on-Sequence Parameters are defined, these will be displayed in addition to any required parameters
In this example, the script contains an error that prevents the script from running (Figure 5)

C. Edit a Sequencer Script

The script can be edited by pressing Edit Script, and any errors corrected.

The script will run when Start Script is pressed. A visual status is displayed in the Progress window, and the current position in the sequence file is also highlighted (Figure 6).

The sequencer can be paused by pressing the Pause Script button (Figure 7).

The progress window will indicated when the sequencer is finished (Figure 8).

Figure 5: There is an error in the script	Figure 6: Sequencer is running

Figure 7: Sequencer is paused	Figure 8: Sequencer is finished
	Figure 8: Sequencer is finished

Sequence file

The following is the contents of the sequence file used for testing test_seq.msl in the example above.

COMMENT "This is a MSL test file"
RUNDESCRIPTION "Test run"
PARAM runs

LOOP $runs
     TRANSITION START
     WAIT ODBvalue "/Equipment/FIFO_acq/Statistics/Events sent" >= 25
     TRANSITION STOP
     WAIT seconds 5
ENDLOOP

Sequencer Page

Contents

Links

Purpose

Access to the Sequencer Page

Features of the Sequencer Page