Hello,

When you click “start” it will probably automatically set the pump rate back to zero, and it won’t necessarily Switch it on.

If you want the pump to run MANUALLY then you need to set the rate to something non zero (like 1) and then click “Switch” on that pump to turn it on.

If you want it to be turned on/off automatically then you need to set it into Turbidostat mode (i.e. “Start” the experiment then click “Regulate OD”) and then provided that the measured OD is less than the OD set-point it will intermittently turn on the pumps.

Does this make sense?

I am afraid if it is going to be that infrequent you will need to do it in the python.
Probably the easiest way to do so would be to add a conditional statement in the main loop of the code (the function runExperiment) which turns the pumps on every 12*60=720 cycles (since each cycle is nominally 60 seconds).
You could to this in a similar way to the function already there to code the terminal which looks like this:

if(sysData[M][‘Experiment’][‘cycles’]%10==9): #Dont want terminal getting unruly, so clear it each 10 rotations.
clearTerminal(M)

In your case you would want it to happen every 720 cycles (i.e. set the top line to have %720=1 or something) and then when that condition is true, set the pump rates to whatever you want and switch them on, and if the condition is false (i.e. add an else statement below it) turn the pumps off.

No worries.
One practical problem you may encounter would be that the pumps will need calibrating to make sure they are injecting the same amount of media as each other. Without this I would guess it might vary by up to 50% between pump heads, since the pumps used are the cheapest ones available!