Siemens A1 ユーザーズマニュアル
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Advanced Applications
MICROMASTER Applications Handbook
51
corresponds to a percentage of the full load current in the motor. In practice it is
not possible to calculate the braking torque this will produce. Continuous use of
the DC braking will cause overheating in the motor and suitable protection systems
must be considered. The braking can also be activated by an external switch.
not possible to calculate the braking torque this will produce. Continuous use of
the DC braking will cause overheating in the motor and suitable protection systems
must be considered. The braking can also be activated by an external switch.
Compound Braking
If DC braking and regenerative braking are combined, braking with minimal
regeneration but with controlled motor speed is possible. This consists of a
reducing frequency with DC component added to it. This braking system,
developed by Siemens for the MICROMASTER, is known as Compound braking.
Compound braking can prove very effective, combining the best of DC braking and
Regenerative braking. As with DC braking, the load energy is dissipated in the
motor, and therefore excessive, frequent braking can lead to overheating.
Parameter P1236 sets the level of compound braking.
regeneration but with controlled motor speed is possible. This consists of a
reducing frequency with DC component added to it. This braking system,
developed by Siemens for the MICROMASTER, is known as Compound braking.
Compound braking can prove very effective, combining the best of DC braking and
Regenerative braking. As with DC braking, the load energy is dissipated in the
motor, and therefore excessive, frequent braking can lead to overheating.
Parameter P1236 sets the level of compound braking.
The above braking methods are summarized in the Figure 8-4.
Frequency Ramp down
DC Braking
Compound Braking
Figure 8-4
Braking Methods
8.3
Using the Serial Interface
All Siemens Drives include a serial interface as standard. The serial interface uses
a RS485 two wire connection which is designed for industrial applications.
a RS485 two wire connection which is designed for industrial applications.
Up to 31drives may be connected on a single RS485 link, and drives addressed
individually or with a broadcast message. A separate master controller is required,
and the drives act as slaves.
individually or with a broadcast message. A separate master controller is required,
and the drives act as slaves.
A communications protocol known as the USS protocol has been developed by
Siemens and is common to all Siemens drive products. Each inverter can be set
up using parameters to receive and respond to USS protocol telegrams.
Siemens and is common to all Siemens drive products. Each inverter can be set
up using parameters to receive and respond to USS protocol telegrams.
Using a serial interface has several advantages:
· Wiring can be greatly reduced.
· Control functions can be changed without re-wiring.