# 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 this 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
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

Parameter | 38.001 AMC Profile Acceleration
--- | ---
Short description | The acceleration rate for the AMC profile generator
Mode | RFC‑A
Minimum | −VM_AMC_RATE_UNIPOLAR | Maximum | VM_AMC_RATE_UNIPOLAR
Default | 1.092 | Units | UU/ms²
Type | 32 Bit User Save | Update Rate | 4ms read
Display Format | Standard | Decimal Places | 3
Coding | RW, VM

The default value of 1.092 UU/ms2 is the equivalent of an acceleration of 1000rpm/s for a feedback device with 16 normalised position bits per revolution and a user unit ratio of unity.

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.

Parameter | 38.002 AMC Profile Deceleration
--- | ---
Short description | The deceleration rate for the AMC profile generator
Mode | RFC‑A
Minimum | −VM_AMC_RATE_UNIPOLAR | Maximum | VM_AMC_RATE_UNIPOLAR
Default | 1.092 | Units | UU/ms²
Type | 32 Bit User Save | Update Rate | 4ms read
Display Format | Standard | Decimal Places | 3
Coding | RW, VM

The default value of 1.092 UU/ms2 is the equivalent of a deceleration of 1000rpm/s for a feedback device with 16 normalised position bits per revolution and a user unit ratio of unity.

See AMC Profile Acceleration (38.001).

Parameter | 38.003 AMC Profile Maximum Speed
--- | ---
Short description | The maximum speed for the AMC profile generator
Mode | RFC‑A
Minimum | 0.00 | Maximum | VM_AMC_SPEED_UNIPOLAR
Default | 1092.00 | Units | UU/ms
Type | 32 Bit User Save | Update Rate | 4ms read
Display Format | Standard | Decimal Places | 2
Coding | RW, VM

The default value of 1092 UU/ms is the equivalent of 1000rpm for a feedback device with 16 normalised position bits per revolution and a user unit ratio of unity.

See AMC Profile Acceleration (38.001).

Parameter | 38.005 AMC Profile Disable
--- | ---
Short description | Set to 1 to disable the AMC profile generator
Mode | RFC‑A
Minimum | 0 | Maximum | 1
Default | 0 | Units |
Type | 1 Bit Volatile | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW

See the introduction to menu 38.

Parameter | 38.006 AMC Profile Input Position
--- | ---
Short description | The input position to the AMC profile generator
Mode | RFC‑A
Minimum | −VM_AMC_POSITION | Maximum | VM_AMC_POSITION
Default |  | Units | UU
Type | 32 Bit Volatile | Update Rate | 4ms write
Display Format | Standard | Decimal Places | 0
Coding | RO, VM, ND, NC, PT

See the introduction to menu 38.

Parameter | 38.007 AMC Profile Input Speed
--- | ---
Short description | The input speed to the AMC profile generator
Mode | RFC‑A
Minimum | −VM_AMC_SPEED | Maximum | VM_AMC_SPEED
Default |  | Units | UU/ms
Type | 32 Bit Volatile | Update Rate | 4ms write
Display Format | Standard | Decimal Places | 2
Coding | RO, FI, VM, ND, NC, PT

See the introduction to menu 38.

Parameter | 38.008 AMC Profile Output Position
--- | ---
Short description | The output position from the AMC profile generator
Mode | RFC‑A
Minimum | −VM_AMC_POSITION | Maximum | VM_AMC_POSITION
Default |  | Units | UU
Type | 32 Bit Volatile | Update Rate | 4ms write
Display Format | Standard | Decimal Places | 0
Coding | RO, VM, ND, NC, PT

See the introduction to menu 38.

Parameter | 38.009 AMC Profile Output Speed
--- | ---
Short description | The output speed from the AMC profile generator
Mode | RFC‑A
Minimum | −VM_AMC_SPEED | Maximum | VM_AMC_SPEED
Default |  | Units | UU/ms
Type | 32 Bit Volatile | Update Rate | 4ms write
Display Format | Standard | Decimal Places | 2
Coding | RO, FI, VM, ND, NC, PT

See the introduction to menu 38.

Parameter | 38.010 AMC Profile Output Acceleration
--- | ---
Short description | The output acceleration of the AMC profile generator
Mode | RFC‑A
Minimum | −VM_AMC_RATE | Maximum | VM_AMC_RATE
Default |  | Units | UU/ms²
Type | 32 Bit Volatile | Update Rate | 4ms write
Display Format | Standard | Decimal Places | 3
Coding | RO, VM, ND, NC, PT

See the introduction to menu 38.

Parameter | 38.011 AMC Profile Jerk 1
--- | ---
Short description | S-ramp profile jerk 1 for the AMC profile generator
Mode | RFC‑A
Minimum | −VM_AMC_JERK_UNIPOLAR | Maximum | VM_AMC_JERK_UNIPOLAR
Default | 0.0000 | Units | UU/ms³
Type | 32 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 4
Coding | RW, 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 ratios.

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 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.

Parameter | 38.012 AMC Profile Jerk 2
--- | ---
Short description | S-ramp profile jerk 2 for the AMC profile generator
Mode | RFC‑A
Minimum | −VM_AMC_JERK_UNIPOLAR | Maximum | VM_AMC_JERK_UNIPOLAR
Default | 0.0000 | Units | UU/ms³
Type | 32 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 4
Coding | RW, VM

See AMC Profile Jerk 1 (38.011).

Parameter | 38.013 AMC Profile Jerk 3
--- | ---
Short description | S-ramp profile jerk 3 for the AMC profile generator
Mode | RFC‑A
Minimum | −VM_AMC_JERK_UNIPOLAR | Maximum | VM_AMC_JERK_UNIPOLAR
Default | 0.0000 | Units | UU/ms³
Type | 32 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 4
Coding | RW, VM

See AMC Profile Jerk 1 (38.011).

Parameter | 38.014 AMC Profile Jerk 4
--- | ---
Short description | S-ramp profile jerk 4 for the AMC profile generator
Mode | RFC‑A
Minimum | −VM_AMC_JERK_UNIPOLAR | Maximum | VM_AMC_JERK_UNIPOLAR
Default | 0.0000 | Units | UU/ms³
Type | 32 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 4
Coding | RW, VM

See AMC Profile Jerk 1 (38.011).

Parameter | 38.015 AMC Profile Update Mode
--- | ---
Short description | Defines when a change to the profile acceleration, deceleration or jerk parameters is applied to the AMC profile generator.
Mode | RFC‑A
Minimum | 0 | Maximum | 1
Default | 1 | Units |
Type | 8 Bit User Save | Update Rate | Background read
Display Format | Standard | Decimal Places | 0
Coding | RW

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