Edwards SCU-350 Series

SCU-350 Series Control Unit for Turbomolecular Pump
MT-21E-201-E
Page 33
3
INSTALLATION
3.13 Setting the rated speed
The STP pump can be set (changed) to the required rated speed in the range of 25,000 to 48,000 rpm
*1
,
in units of 500 rpm. The setting can be performed even during rotation of the STP pump. The rated
speed is set to 48,000 rpm
*1
at delivery.
The rated speed setting mode is entered by setting dip switch 1 of DSW-B on the top panel to the ON
position. The rated speed is set to 48,000 rpm
*1
(initial setting) by setting dip switch 1 to the OFF
position. For the position of the DSW-B switch, see Figure 11, "SCU-350 top panel".
Prepare the following tool for setting the rated speed:
Small-sized screwdriver
3.13.1 When setting DSW-B No. 1 to ON under power-on state
1. Set dip switch 1 of DSW-B to the ON position. The LCD displays "SET= ***00rpm" which indicates
the rated speed setting mode. The speed displayed here depends on the current position dialled
with the VR1 volume on the top panel.
2. Turning the VR1 volume on the top panel changes the value "***00rpm" on the rated speed setting
display "SET= ***00rpm". Turn the VR1 volume clockwise to increase the rated speed, or counter
clockwise to decrease the rated speed, until the required rated speed is displayed. Note that the
rated speed is not yet determined in this state.
3. To determine the rated speed displayed in "SET= ***00rpm," press the "START" switch. When the
STP pump is in the ACCELERATION or NORMAL OPERATION state, it accelerates or
decelerates up to the set value of rated speed. When the STP pump is in the LEVITATION or
BRAKE state, the pump's state remains unchanged. Note that the rated speed is not determined if
the "START" switch is pressed when the LCD message is other than "SET= ***00rpm".
4. Press the "SELECT" switch once, and the LCD displays the set value of rated speed in "RATING:
***00rpm". Make sure the required rated speed is displayed. If the required speed is not displayed
or the rated speed is to be changed again, press the "SELECT" switch to display "SET= ***00rpm"
again. Then, perform steps 2) and 3) again to set the rated speed.
5. When the STP pump is in the LEVITATION or BRAKE state, perform STP pump rotation operation
to rotate it. The STP pump accelerates up to the rated speed.
*1
44,000 rpm with SCU-350D/350DA