Menu 38 − AMC Profile Generator

Mode: RFC‑A

Profile generator

Main profile

AMC Profile Input Speed (38.007) is the rate of change of position over each sample from any of the references. This provides the speed target for the profile generator and is integrated to give AMC Profile Input Position (38.006) which is the position target. When the profile generator is enabled it produces AMC Profile Output Speed (38.009) which is the rate of change of output position and this is integrated to give AMC Profile Output Position (38.008). Depending on the profile mode the profile generator aims to make either the AMC Profile Output Speed (38.009) equal to the AMC Profile Input Speed (38.007), the AMC Profile Output Position (38.008) equal to the AMC Profile Input Position (38.006) at zero speed, or both. The profile target mode depends on the input to the profile generator as follows.

Input Target
AMC Stop Reference (34.002) Stop reference at zero speed
AMC Position Reference (34.003) (AMC Reference Select (34.007) = 1 or 6) Position reference at zero speed
AMC Speed Reference (34.006) Speed reference speed
Cam Profile disabled
Electronic gearbox with non-rigid lock

Input speed when not locked
Profile disabled when locked

Electronic gearbox with rigid lock

Input speed and position when not locked
Profile disabled when locked

Homing system

Input speed while finding home position
Input position at zero speed when moving to home reset position

Profile input position (AMC Reference Select (34.007) = 7) Constant target position at zero speed

The profile generator can operate with a linear ramp (AMC Profile Jerk 1 (38.011) = 0) or an s-ramp profile (AMC Profile Jerk 1 (38.011) > 0). When the profile is operating in linear mode the rate of change of AMC Profile Output Speed (38.009) is constrained by the profile generator. If an s-ramp profile is enabled the rate of change of acceleration is also constrained and up to four unique jerk values can be defined, see AMC Profile Jerk 1 (38.011).

If the profile generator is disabled AMC Profile Output Speed (38.009) = AMC Profile Input Speed (38.007) and AMC Profile Output Position (38.008) = AMC Profile Input Position (38.006). The profile generator can be disabled under any of the following conditions.

Conditions for profile generator disable Comments
AMC Profile Disable (38.005) = 1 Profile disabled by the user
AMC Reference Select (34.007) = 0
and AMC Stop Mode (34.001) = 1 or 3
Stop reference selected and no profile stop required
Cam system enabled
(i.e. AMC Reference Select (34.007) = 3)
The Cam system provides its own profile, and so the profile generator is not required
AMC EGB Locked (37.006) = 1 Electronic gearbox output is locked and should follow the master position without any delay


Parameter38.001  AMC Profile Acceleration
Short description 
ModeRFC‑A
Minimum−VM_AMC_RATE_UNIPOLARMaximumVM_AMC_RATE_UNIPOLAR
Default1.092UnitsUU/ms²
Type32 Bit User SaveUpdate Rate4ms read
Display FormatStandardDecimal Places3
CodingRW, VM

The default value of 1.092 UU/ms2 is the equivalent of an acceleration of 1000rpm/s for a 16 bits per revolution feedback device with a user units ratio = 1.

The profile generator applies the constraints to the output speed defined by AMC Profile Acceleration (38.001) when the speed is moving away from 0, AMC Profile Deceleration (38.002) when the speed is moving towards 0, and AMC Profile Maximum Speed (38.003) in either direction.


Parameter38.002  AMC Profile Deceleration
Short description 
ModeRFC‑A
Minimum−VM_AMC_RATE_UNIPOLARMaximumVM_AMC_RATE_UNIPOLAR
Default1.092UnitsUU/ms²
Type32 Bit User SaveUpdate Rate4ms read
Display FormatStandardDecimal Places3
CodingRW, VM

The default value of 1.092 UU/ms2 is the equivalent of a deceleration of 1000rpm/s for a 16 bits per revolution feedback device with a user units ratio = 1.

See AMC Profile Acceleration (38.001).


Parameter38.003  AMC Profile Maximum Speed
Short description 
ModeRFC‑A
Minimum−VM_AMC_SPEED_UNIPOLARMaximumVM_AMC_SPEED_UNIPOLAR
Default1092.00UnitsUU/ms
Type32 Bit User SaveUpdate Rate4ms read
Display FormatStandardDecimal Places2
CodingRW, VM

The default value of 1092 UU/ms is the equivalent of 1000rpm for a 16 bits per revolution device with a user units ratio = 1.

See AMC Profile Acceleration (38.001).


Parameter38.005  AMC Profile Disable
Short description 
ModeRFC‑A
Minimum0Maximum1
Default0Units 
Type1 Bit VolatileUpdate RateBackground read
Display FormatStandardDecimal Places0
CodingRW

See the introduction to menu 38.


Parameter38.006  AMC Profile Input Position
Short description 
ModeRFC‑A
Minimum−VM_AMC_POSITIONMaximumVM_AMC_POSITION
Default UnitsUU
Type32 Bit VolatileUpdate Rate4ms write
Display FormatStandardDecimal Places0
CodingRO, VM, ND, NC, PT

See the introduction to menu 38.


Parameter38.007  AMC Profile Input Speed
Short description 
ModeRFC‑A
Minimum−VM_AMC_SPEEDMaximumVM_AMC_SPEED
Default UnitsUU/ms
Type32 Bit VolatileUpdate Rate4ms write
Display FormatStandardDecimal Places2
CodingRO, FI, VM, ND, NC, PT

See the introduction to menu 38.


Parameter38.008  AMC Profile Output Position
Short description 
ModeRFC‑A
Minimum−VM_AMC_POSITIONMaximumVM_AMC_POSITION
Default UnitsUU
Type32 Bit VolatileUpdate Rate4ms write
Display FormatStandardDecimal Places0
CodingRO, VM, ND, NC, PT

See the introduction to menu 38.


Parameter38.009  AMC Profile Output Speed
Short description 
ModeRFC‑A
Minimum−VM_AMC_SPEEDMaximumVM_AMC_SPEED
Default UnitsUU/ms
Type32 Bit VolatileUpdate Rate4ms write
Display FormatStandardDecimal Places2
CodingRO, FI, VM, ND, NC, PT

See the introduction to menu 38.


Parameter38.010  AMC Profile Output Acceleration
Short description 
ModeRFC‑A
Minimum−VM_AMC_RATEMaximumVM_AMC_RATE
Default UnitsUU/ms²
Type32 Bit VolatileUpdate Rate4ms write
Display FormatStandardDecimal Places3
CodingRO, VM, ND, NC, PT

See the introduction to menu 38.


Parameter38.011  AMC Profile Jerk 1
Short description 
ModeRFC‑A
Minimum−VM_AMC_JERK_UNIPOLARMaximumVM_AMC_JERK_UNIPOLAR
Default0.0000UnitsUU/ms³
Type32 Bit User SaveUpdate RateBackground read
Display FormatStandardDecimal Places4
CodingRW, VM

If AMC Profile Jerk 1 (38.011) > 0 and AMC Rate Selected (31.013) >= 1ms the maximum rate of change of AMC Profile Output Acceleration (38.010) is constrained by the jerk parameters in AMC Profile Generator (38). Note that it is only possible to change between the s-ramp profile and the linear profile when the drive or motion controller is disabled.

Jerk configuration

It is possible to configure up to four independent jerk values as shown in the diagram below.

To minimise the error between AMC Profile Input Position (38.006) and AMC Profile Output Position (38.008) after the initial profile has been completed the maximum values of AMC Profile Jerk 3 (38.013) and AMC Profile Jerk 4 (38.014) which are used during the profile are limited to the following values.

AMC Profile Jerk 3 (38.013) ≤ 100 × AMC Profile Jerk 4 (38.014)

AMC Profile Jerk 4 (38.014) ≤ 100 × AMC Profile Jerk 3 (38.013)

If any of the jerk parameters are set to zero the jerk used in that section is inherited from the previous section. This allows the s-ramp to be setup in one of the following configurations without changing all of the jerk parameters individually. If a linear change of speed is required in a section of the s-ramp the corresponding jerk parameter must be set to a value that ensures that the maximum rate (AMC Profile Acceleration (38.001) or AMC Profile Deceleration (38.002)) is achieved in a single sample. 

Note that if AMC Profile Update Mode (38.015) is configured to allow a change of jerk during a profile and AMC Profile Jerk 1 (38.011) is set to zero before the profile has been completed the minimum jerk (0.0001 uu/ms3) will be used by the profile until AMC Profile Output Speed (38.009) reaches standstill.  

Profile 1 - Single jerk

AMC Profile Jerk 1 (38.011) > 0

AMC Profile Jerk 2 (38.012) = 0

AMC Profile Jerk 3 (38.013) = 0

AMC Profile Jerk 4 (38.014) = 0

Profile 2 - Acceleration and deceleration jerk

AMC Profile Jerk 1 (38.011) > 0

AMC Profile Jerk 2 (38.012) = 0

AMC Profile Jerk 3 (38.013) > 0

AMC Profile Jerk 4 (38.014) = 0

Profile operation

If AMC Profile Output Speed (38.009) crosses the zero boundary without stopping (i.e. AMC Speed Reference (34.006) is changed from a positive to negative value) AMC Profile Output Acceleration (38.010) is limited by the deceleration parameters (AMC Profile Deceleration (38.002)AMC Profile Jerk 3 (38.013) and AMC Profile Jerk 4 (38.014)) until the acceleration is reduced to zero (constant speed) as shown in the diagram below.   

The above description also applies when the s-ramp is operating in position mode. If AMC Profile Input Position (38.006) is changed when the output of the profile is at standstill (AMC Profile Output Speed (38.009) and AMC Profile Output Acceleration (38.010) = 0) the profile will accelerate to the target speed under the constraints of AMC Profile Acceleration (38.001)AMC Profile Jerk 1 (38.011) and AMC Profile Jerk 2 (38.012) and decelerate to zero speed under the constraints of AMC Profile Deceleration (38.002), AMC Profile Jerk 3 (38.013) and AMC Profile Jerk 4 (38.014). This is shown in the diagram below. Note that when AMC Profile Complete Window (41.005) is set to zero AMC Profile Complete Flag (41.006) can be used to detect when the output of the profile has reached the target position and is at standstill.

If AMC Profile Input Position (38.006) is changed before the profile has been completed and AMC Profile Output Speed (38.009) must cross the zero boundary to reach the new target speed the profile will be constrained by the deceleration parameters for the entire movement as shown in the diagram below.  

 


Parameter38.012  AMC Profile Jerk 2
Short description 
ModeRFC‑A
Minimum−VM_AMC_JERK_UNIPOLARMaximumVM_AMC_JERK_UNIPOLAR
Default0.0000UnitsUU/ms³
Type32 Bit User SaveUpdate RateBackground read
Display FormatStandardDecimal Places4
CodingRW, VM

See AMC Profile Jerk 1 (38.011).


Parameter38.013  AMC Profile Jerk 3
Short description 
ModeRFC‑A
Minimum−VM_AMC_JERK_UNIPOLARMaximumVM_AMC_JERK_UNIPOLAR
Default0.0000UnitsUU/ms³
Type32 Bit User SaveUpdate RateBackground read
Display FormatStandardDecimal Places4
CodingRW, VM

See AMC Profile Jerk 1 (38.011).


Parameter38.014  AMC Profile Jerk 4
Short description 
ModeRFC‑A
Minimum−VM_AMC_JERK_UNIPOLARMaximumVM_AMC_JERK_UNIPOLAR
Default0.0000UnitsUU/ms³
Type32 Bit User SaveUpdate RateBackground read
Display FormatStandardDecimal Places4
CodingRW, VM

See AMC Profile Jerk 1 (38.011).


Parameter38.015  AMC Profile Update Mode
Short description 
ModeRFC‑A
Minimum0Maximum1
Default1Units 
Type8 Bit User SaveUpdate RateBackground read
Display FormatStandardDecimal Places0
CodingRW

AMC Profile Update Mode (38.015) can be used to select when a change to the profile acceleration, deceleration or jerk parameter is applied to the profile generator.

AMC Profile Update Mode (38.015) Profile update Ramp type
0                                                     Profile acceleration, deceleration and jerk values are updated in the sample after the parameter has been read by the drive. Linear ramp and S-ramp
1

When the s-ramp profile is enabled (AMC Profile Jerk 1 (38.011) > 0) the profile acceleration, deceleration and jerk values are only updated when the output of the profile generator is at standstill (speed and acceleration = 0). This prevents a change to the profile constraints causing an overshoot of the target speed or position. Note that an overshoot can still occur if the target speed or position is changed when the profile generator is not at standstill. If the profile generator is disabled (see the introduction to menu 38) or the linear ramp is enabled the profile parameters are updated as described in the previous mode.  

S-ramp