Test RST

Accessing genie_python commands

From an Ibex scripting terminal, genie_python commands can be accessed via the g namespace. For example: g.get_version()

You should have noticed immediately after you typed g. that an autocomplete window appeared:

.. image:: AutoCompleteWindowBasic.png

The window lists the available commands, and the arguments they take in brackets. You also notice that a description of the highlighted functions and its arguments is also given. The list will be refined as you type more characters.

Instrument control

Instrument control commands let you switch between experimental states. The most common commands are:

• begin: Begins a new run
• pause: Pauses the current run
• resume: Resumes the current run
• end: Ends the current run
• abort: Aborts the current run

Each of the commands above accepts an optional boolean parameter. Setting it to True (e.g. g.begin(True)) will give extra output from the DAE. The default is non-verbose output.

If you need to get the current state, you can use:

• get_runstate: Gets the states of the current run

WARNING: Switching states may not always lead to the assumed state. For example, you may run "g.begin()" and then expect the instrument to be running. It could be, but it could also be waiting, vetoing, or still setup. It's a good idea to put checks into your scripts that you've reached the expected state before continuing.

You can update and store DAE results using:

• update: Load the data from the DAE into memory
• store: Write the updated DAE information to disk
• updatestore: Load the data from the DAE into memory and store it to disk

Worked example

The following script will begin and run, then stop it once it reaches a running state::

import time

# Only start if we're in the correct state
if g.get_runstate=="SETUP"
    g.begin()

    maximum_retries = 60
    for i in range(maximum_retries):
        if g.get_runstate()=="RUNNING":

            # A function that does the sequence of operations associated with the run
            do_experimental_stuff()

            # We're done, exit the loop
            break

        else:
            # Wait for a second before checking again
            time.sleep(1)
    else:
        "Could not reach a running state"

Blocks

• get_blocks: Gets a list of the currently available blocks

• cshow: Shows the properties of a named block/all blocks

  • If given a name (e.g. MY_BLOCK) it will return a string containing properties of the block
    • Example: MY_BLOCK = 10 (runcontrol = NO, lowlimit = 0.0, highlimit = 0.0)
  • If called without arguments, it will show the same information for all blocks, with each block on a new line

• cget: Gets properties of a named block as a dictionary of values

  • Example: MY_BLOCK = 10 (runcontrol = NO, lowlimit = 0.0, highlimit = 0.0)

  • Unlike cshow, a block name must be specified

  • Properties can be accessed as standard Python::

    block_info = g.cget("MY_BLOCK") name = block_info("name") value = block_info("value") print "The value of block {0} is {1}".format(name, value)

• cset: Sets the value for a particular block

  • Assumes that either a setpoint exists for the underlying value or the block itself points at a setpoint
  • Can be called with block names as named arguments. This is useful for setting multiple blocks
    • Example: g.cset(MY_BLOCK=1, MY_OTHER_BLOCK=2)
  • The block can also be passed in by name. This is useful when setting advanced block properties
    • Example: g.cset("MY_BLOCK", lowlimit=1, highlimit=10, runcontrol=True)

Run control

Experiment setup

Exercise 2

• This exercise requires the following pre-requisites. These should be satisfied if you are following this as part of the Ibex-run training course
  • You have permission to begin and end runs on the instrument you're using.
  • The instrument your using has been configured so it can successfully enter a running state
  • You have a settable block called "MY_BLOCK"
• Change the title of the run to "Exercise 2"
• Begin a new run
• Pause the run
• Set the value of "MY_BLOCK" to 5, with a high limit of 10, a low limit of 1 and put it under run control
• Resume the run
• Set the value of "MY_BLOCK" to 20
• Confirm (using genie_python) that the instrument has entered a waiting state
• End the run

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