Siemens SIMATIC ET 200pro - Selecting the Control Mode

Commissioning
6.2 Preparing for commissioning
SIMATIC ET 200pro FC-2 converter
70 Operating Instructions, 04/2015, FW V4.7.3, A5E34257324B AB
6.2.2
Selecting the control mode
Criteria for selecting either U/f control or vector control
U/f control or flux current control
Vector control without an encoder
Application
examples
• Pumps, fans, and compressors with flow
characteristic
• Wet or dry blasting technology
• Horizontal conveyor technology (conveyor
belts, roller conveyors, chain conveyors)
• Basic spindles
• Pumps and compressors with displacement
machines
• Extruder
Properties of
closed-loop motor
control
• The closed-loop control is insensitive to
inaccurate motor data settings, e.g. the mo-
tor temperature
• Can be commissioned with just a few set-
tings.
• Responds to speed changes with a typical
settling time of 100 ms … 200 ms
• Responds to load surges with a typical set-
tling time of 500 ms
• U/f and FCC are suitable for the following
cases:
– For ramp-up times 0 → rated speed > 2 s
– For applications with increasing load
torque without load impulses
• The vector control uses the converter, the mo-
tor and the mechanics highly efficiently (maxi-
mum motor voltage = 95% of the mains
voltage).
• The vector control responds to speed changes
with a typical settling time of < 100 ms.
• The vector control responds to load impulses
with a typical settling time of 20 ms.
• The vector control is required in the following
cases:
– For ramp-up times 0 → rated speed < 2 s
– For applications with fast and high load im-
pulses
– For heavy duty starting using ≤ 90% of the
stall torque of the motor
• Vector control typically achieves a torque accu-
racy of ± 5% for 10% … 100% of the rated
speed
Max. output
frequency
550 Hz 240 Hz