Exercise Solutions

Exercise 1

Opening a scripting window should be straightforward if IBEX is installed correctly. Once you’ve opened the scripting perspective, check for the following
- Ideally the instrument will appear as SETUP
- The output when the scripting window opens should look a bit like this:

../../_images/StandardStartupOutputOnDemo.png

To print the message, enter something like print "Hello, World! and press return
The square of the integers between 1 and 10 can be output with the code below. A blank line will indicate to the scripting window that you’ve finished writing the loop and it can go ahead and be executed.:

for i in range(1,11):
    print i*i

Exercise 2

From Exercise 2

Use g.change_title("Exercise 2") to change the title
The following code will start the run, wait, and then pause:

g.begin()
g.waitfor_uamps(1)
g.pause()

This code sets the value, run control, and limits on “MY_BLOCK”. Your code may look slightly different depending how you’ve chosen to pass in the arguments:

g.cset("MY_BLOCK", 5, lowlimit=1, highlimit=10, runcontrol=True)

The following resumes the run:

g.resume()

This code will set the block value and check the subsequent state:

# Can use either way of specifying cset for a single block
g.cset(MY_BLOCK=20)

# Can verify in any sensible way, so long as we're getting g.get_runstate()
if g.get_runstate()=="WAITING":
    print "The instrument is waiting"
else:
    print "The instrument is not waiting"

The following code will scan the block from its original value down to 4. It assumes the initial value is greater than 4:

for i in range(int(g.cget("MY_BLOCK")['value']), 4, -1):
    g.cset(MY_BLOCK=i)
    g.waitfor_time(seconds=1)

This function will end the run:

g.end()

Exercise 3

From Exercise 3a.

(a) After creating the files, you should have one new file in C:\scripts and another in C:\Instrument\Settings\config\[Instrument name]\Python\inst
(b) The function in set_up_instrument.py should look something like this:

def set_up_instrument():
g.change_title(“My experiment”) g.change_user(“Adrian”)
(b) The function in run_my_experiment.py should look something like this:

def get_uamps_run():
    g.begin()
    # Assume this doesn't change
    period = g.get_period()
    for i in range(10):
        print "Total current after {0}s: {1}.format(i+1, g.get_uamps(period))
        g.waitfor_time(seconds=1)
    g.end()

(c) This will load the user script: g.load_script("run_my_experiment.py")
(d) This will run the instrument script: inst.set_up_instrument()
(e) This will run the function from the user script get_uamps_run()

Exercise 4

From Exercise 4.

You should have created a Python file in C:\Instrument\Settings\config\[Machine name]\Python\inst that contains something like the following:

from genie_python import genie as g, BLOCK_NAMES as b

def ramp(block, target):
    try:
        initial = g.cget(block)['value']
    except:
        print "Problem getting value for block {0}. Make sure it exists".format(block)
    else:
        g.change_title("Ramping {0} from {1} to {2}".format(block, initial, target))
        g.begin()

        current = initial
        small = 0.0001
        while abs(current-target) > small:
            current = min(target, current + 1) if initial < target else max(target, current -1)
            g.cset(block, current)
    finally:
        g.end()

Once you add the line to output the current title, the top of your file should look like this:

print g.get_title()
def ramp(block, target):
    ...

This user-defined function will ramp the two blocks using the instrument function:

def ramp_two_blocks():
    for block, target in [("MY_BLOCK", 10), ("MY_OTHER_BLOCK", -10)]:
        inst.ramp(block, target)

To load the user script, assuming the file is called “ramp_blocks.py”, run the following from the scripting perspective:

g.load_script("C:\scripts\ramp_blocks.py")
ramp_two_blocks()

You should have seen the current title printed during the initialisation of the scripting window