STP-iS2207 Series Turbomolecular Pump
MT-89E-001-C
Page
61
4
4.9.3 Second speed option
When the second speed option is enabled, second rating speed can be set independently of the normal
rating speed setting. The selection of the second rating speed and normal rating speed are operated
from I/O remote input or serial communication port.
The second speed setting is changed from serial communication port, or STP-Link. (see Section 5.4,
"Command specifications")
Table 13 shows pump status in the state of speed selection.
Pump status
Difference between
Normal Speed and
Second Speed Setting
is more than
approximately 10%
When the rotational speed becomes low, the STP pump enters
BRAKE mode, and then decelerates.
When the rotational speed becomes high, the STP pump enters
ACCEL mode, and then accelerates.
The STP pump will enter the normal mode when the rotational speed
attains within +10% of speed setting.
NORMAL
BRAKE
ACCEL
NORMAL NORMAL
Pump status
Speed Set Point
Second Speed Set Point
Second Speed Set Point -10%
Second Speed Set Point +10%
Speed Set Point +10%
Speed Set Point -10%
Second speed select
OFF ON OFF
Rotational speed
Difference between
Normal Speed and
Second Speed Setting
is approximately 10% or
less
The rotational speed changes in the normal mode.
NORMAL
Pump status
Speed Set Point
Second Speed Set Point
Second Speed Set Point -10%
Second Speed Set Point +10%
Speed Set Point +10%
Speed Set Point -10%
Second speed select
OFF ON OFF
Rotational speed
Table 13 - Second speed function