Ulvac UTM300B, Instruction Manual

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6.4 Shutting Down
6.4.4 Shutting Down Sequence in RS-485 communication
(1) Input the "STOP" command via RS-485 communication.
The pump deceleration starts. Status is changed from "NORMAL" or "ACCELERATION"
to "IDLE".
(2) Wait until status changes to "STOP" status.
(3) Shut the power off.
Further, in such a case when a hydraulic rotary vacuum pump is used as backing vacuum
pump and there is possible reverse flow and diffusion of oil from the backing vacuum pump,
return the pump internal pressure to atmospheric pressure using dry nitrogen gas, after complete
shut-down of the pump NORMAL lamp goes out, to prevent the turbo molecular pump from being
contaminated with oil vapor.
For shutting down the turbo molecular pump in running at high speed with infeed of dry nitrogen
gas to the pump, keep the nitrogen gas flow rate at 1500 mL/min maximum.
REFERENCE (shutting down procedure)
In order to avoid contamination of vacuum chamber by vapor of bearing grease, it recommends
returning the inside of TMP to atmospheric pressure using a venting valve.