increasing max dilution

Andrew Morgenthaler

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Mar 31, 2017, 2:00:35 PM3/31/17

to mixture-control...@googlegroups.com

Is there a way on the turbidostat to increase the max dilution volume? The max is currently '160' but it doesn't appear to depress the syringe all the way, nor does it use the full volume of the syringe. I figure the latter is due to the fact that the servo gears would hit the floor, but maybe they could be shortened? Hypothetically since we can suck up a max of 1800pmv during manual command of the syringe, shouldn't we be able to dispense a max of 225pmv (1800 divided by 8) per chamber?

-Andrew

Chris Takahashi

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Mar 31, 2017, 5:10:33 PM3/31/17

to Mixture Controlled Turbidostat, Andrew.Mo...@colorado.edu

Yeah this is possible. 160 is conservative. some of the distance gets used by the backlash compensation (it over withdraws and dispenses some amount back into the media bottle, I forget exactly how many counts). I think maybe 200 would be safe. Your best bet is to get a bigger syringe though.

anmo...@colorado.edu

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Mar 31, 2017, 5:18:51 PM3/31/17

to Mixture Controlled Turbidostat, Andrew.Mo...@colorado.edu

If I were to use a bigger syringe would I have to change anything in the python code to accommodate for the change in volume?

Chris Takahashi

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Mar 31, 2017, 5:23:08 PM3/31/17

to Mixture Controlled Turbidostat, Andrew.Mo...@colorado.edu

In theory to get the same Kp an Ki values you'd have to scale them by the same factor of syringe sectional area.

ie if old syringe had a radius of Ro and the new had a radius of Rn then i'd set

Kpnew = Kpold *(Ro/Rn)^2

Kinew = Kiold *(Ro/Rn)^2

in practice it probably won't matter much. But if you find it does i'd start with the above.

On Friday, March 31, 2017 at 2:18:51 PM UTC-7,

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