Rotation scans timeout at long exposures due to top up wait

[olliesilvester]

With long (~0.1s) exposures, data collections can take 6 minutes or more. If Hyperion is about to start a 6 minute collection, but there is a top-up due in 5 minutes, it will wait for 5 minutes before starting. The timeout for rotations is currently 10 minutes, so this causes an error.
The simplest solution would just be to increase the time-out to ~30 mins. There are some more involved alternatives though:

• Instead of waiting for top-up, start collection anyway and then pause during top-up.

• While waiting for top-up, pause the rotation timeout timer

[olliesilvester]

After discussion with Neil, for exposure times greater than a certain value, we can just continue with collection during top-up and not worry about waiting, since the flickering beam doesn't affect things very much

[DominicOram]

To work out what those values are take a look at the GDA properties:

gda.mx.topup.enabled = true
gda.mx.topup.threshold_percentage = 20
gda.mx.topup.instability_time = 27

and associated code. We think it's something like "if topup instability time >20% of total exposure then wait"