Hi everyone,
We are running 30 mL working culture in 60 mL vials with Pioreactor 20 mL v1.1 model. The reactors are placed inside the laminar flow bench and heated using thermostat. However, the pioreactors stabilize at lower temperature than the target temperature. As illustrated below, 3 pioreactors were set to 37C but they stabilize around 32-34C.
The laminar flow bench is continuously ventilated which can make it a bit more difficult to heat up the reactors. However, the heating PCB units should be able to support heat higher than 37C, and hence, should be able to reach the target temperature right? The configuration settings are not changed and different tests with different reactors resulted with similar outcomes.
Has anyone experienced similar issue or can Pioreactor confirm if this could be a hardware limit of the heating PCB?
Hi @sharknaro,
Hm, you can test if the heater PCB is limited by checking it’s PWM output. On the command line of any worker, try:
pio cache view pwm_dc
and look for what channel 18 is doing. If it’s at 100%, it is fully on and can’t heat anymore. (Check that cache over the span of a few minutes, btw).
Also check the logs for any warnings about over heating, something like “Temperature of heating surface has exceeded” - if this occurs, we might throttle the power of the heater.
I would agree that 37C should be achievable in this set up.
Yes, cannel 18 is works at 100% during heating. There is no warning in the logs. Also I tested running 15 mL culture on the table top and this was the outcome:
The test run was done with:
- Pioreactor 20 mL v1.1 setup
- 15 mL water
The reactor was placed close to a window which did not have any curtains. It seems the temperature started to increase in the dawn. Hence, maybe the reason for not reaching 37C is because the working environment is too cool? Though now the channel 18 is changing between 98-100% but the temperature can still be kept at 37C, which puzzles me.
