BSVT Concept
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13.2.1 State Off / Standby
This state is active when the BSVT is switched off. In general, the thermal energy of the
system is kept as steady as possible (sub state off):
• Heater(s) = off
• Chiller = off
• Gas flow = standby gas flow (between 0 and maximum)
Nevertheless, it is possible that the system loses energy (e. g. chilling by active CryoProbe),
and the temperature drops below the minimum allowed temperature. In this case, a minimum
heating is activated, and the control logic goes into the sub state antifreeze protection:
• Heater(s) = on, regulating for temperature next to room temperature
• Chiller = off
• Gas flow = operating gas flow (between minimum and maximum)
If the measured temperature stays below the minimum temperature even if the antifreeze
heating is active, then the sample is lifted for protection (sub state sample protection). As
soon as the temperatures are in range again, the sample is transported to its original location.
13.2.2 State On / Operating
This state is active when the BSVT is switched on. All devices of the BSVT configuration are
active:
• Heater(s) = Regulating for required target temperature(s).
• Chiller = According to user settings.
• Gas flow = Operating gas flow (between minimum and maximum).
The PID controller parameters can be optimized by a self-tune operation. If the global self-
tune procedure is activated, then all active channels are tuned in parallel. As soon as the self-
tune of a channel is complete, the according channel is starting operational temperature
regulation.
Self-tuning can be started from both states – off / standby and on / operating. If it fails in the
end, then the BSVT is switched off unless the self-tuning has been started from on/operation
and the measured temperatures have been close to the aimed values.
It is possible to add further devices to the BSVT configuration while the temperature control is
on / operating. The added devices stay inoperable (no active temperature regulation) and
provide only temperature measurement. As soon as the BSVT is switched off, the pending
changes are handled, and the BSVT configuration is updated.
However, if devices that are involved in temperature regulation are removed during operation
then the BSVT stops its activity.
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General