Constant Speeds/Frequencies - ABB ACS380 Firmware Manual

ACS380 FW.book Page 68 Friday, May 4, 2018 4:18 PM
68 Program features
Settings
• Speed reference ramping - Parameters 23.11...23.15,
193), 23.33 Shape time 2
• Torque reference ramping - Parameters
26.18 Torque ramp up time
202).
• Frequency reference ramping - Parameters
scaling (page 289).
• Jogging - Parameters
jogging (page 191).
• Motor potentiometer - Parameter
187).
• Emergency stop ("Off3" mode) - Parameter
192).


Constant speeds/frequencies

Constant speeds and frequencies are predefined references that can be quickly
activated, for example, through digital inputs. It is possible to define up to 7 speeds
for speed control and 7 constant frequencies for frequency control.
WARNING: Speeds and frequencies override the normal reference
irrespective of where the reference is coming from.
Settings
Parameter groups
reference chain (page 203).

Critical speeds/frequencies
Critical speeds (sometimes called "skip speeds") can be predefined for applications
where it is necessary to avoid certain motor speeds or speed ranges because of, for
example, mechanical resonance problems.
The critical speeds function prevents the reference from dwelling within a critical band
for extended times. When a changing reference enters a critical range, the output of
the function freezes until the reference exits the range. Any instant change in the
output is smoothed out by the ramping function further in the reference chain.
When the drive is limiting the allowed output speeds/frequencies, it limits to the
absolutely lowest critical speed (critical speed low or critical frequency low) when
accelerating from standstill, unless the speed reference is over the upper critical
speed/ frequency limit.
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(page 193) and 46.01 Speed scaling
01.30 Nominal torque scale
(page 202) and
23.20 Acc time jogging
22.75 Motor potentiometer ramp time
22 Speed reference selection
23.32 Shape time 1
(page 289).
(page 117),
26.19 Torque ramp down time
28.71...28.75 and 46.02 Frequency
(page 191) and 23.21 Dec time
(page
23.23 Emergency stop time (page
(page 177) and 28 Frequency
(page
(page