Stopping and Braking Attributes
These are the active stopping and braking related attributes associated with a Motion
Control Axis.
AC Injection Brake Frequency Threshold
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - D (IM) | Set/SSV | REAL | 1 | 0 |  | Hz |
Value that sets the frequency that initiates the transition from AC injection braking to DC
injection braking when executing an “AC Injection Brake” Stopping Action. When the output
frequency drops below this threshold during the braking operation, the transition from AC
injection braking to DC injection braking occurs.
AC Injection Brake Power Threshold
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - D (IM) | Set/SSV | REAL | 1 | 0 | | % |
Value that adjusts the drive’s internally defined power threshold that initiates the
transition from AC injection braking to DC injection braking when executing an “AC Injection
Brake” Stopping Action. When the output power level drops below this threshold during the
braking operation, the transition from AC injection braking to DC injection braking occurs.
A value of 100% results in the drive using 100% of its internally defined power threshold
when checking for this transition condition.
AC Injection Brake Regulator Ki
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - D (IM) | Set/SSV | REAL | 0.1 | 0 | | (Hz/Volt)/Sec |
Value that sets the proportional gain of the regulator that controls the output frequency
applied to the motor based on the DC bus voltage when executing an “AC Injection Brake”
Stopping Action.
AC Injection Brake Regulator Kn
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - D (IM) | Set/SSV | REAL | 0.1 | 0 | | Hz/Volt |
Value that sets the proportional gain of the regulator that controls the output frequency
applied to the motor based on the DC bus voltage when executing an “AC Injection Brake”
Stopping Action.
AC Injection Brake Regulator Kp
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - D (IM) | Set/SSV | REAL | 0.0015 | 0 | | Hz/Volt |
Value that sets the proportional gain of the regulator that controls the output frequency
applied to the motor based on the DC bus voltage when executing an “AC Injection Brake”
Stopping Action.
Stopping Action
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Required - XD | Set/SSV# | USINT | Eq 23 1 for C 0 for F 0 for X | - | - | Enumeration: 0 = Disable & Coast 1 = Current Decel & Disable 2 = Ramped Decel & Disable 3 = Current Decel & Hold 4 = Ramped Decel & Hold 5-127 = (reserved) 128-255 = (vendor specific) 128 = DC Injection Brake 129 = AC Injection Brake |
# Indicates the attribute cannot be set while the tracking command (Tracking Command bit in CIP Axis Status is true). | ||||||
When disabling or aborting an axis, through a Disable Request or an Abort Request this
value determines the stopping method to apply to the motor. Each supported Stopping Action
initiates one of three Stopping Sequences (IEC60204-1 Category Stops 0, 1, and 2).
- In the case of a Disable Request, the stopping method is applied while in the Stopping state and the final state after the stopping method is completed is the Stopped state.
- In the case of an Abort Request, the stopping method is applied while in the Aborting state and the final state after the stopping method completes is the Major Faulted state.
In either final state the device's inverter power structure will either be Disabled
(Disable selection) and free of torque or actively held (Hold selection) in a static
condition. This attribute has no impact or relationship to the planner generated
acceleration and deceleration profiles. This attribute does not, in any way, determine the
stopping actions applied in response to fault conditions.
Connection Loss Stopping Action
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - XD | Set/SSV# | USINT | Eq 23 1 for C 0 for F 0 for X | - | - | 0 = Disable and Coast 1 = Current Decel and Disable 2 = Ramped Decel and Disable 3 = Current Decel and Hold 4 = Ramped Decel and Hold 5-127 = Reserved 128 = DC Injection Brake 129 = AC Injection Brake 130-255 = Vendor Specific |
# Indicates the attribute cannot be set while the tracking command (Tracking Command bit in CIP Axis Status is true). | ||||||
When a CIP Motion connection loss is detected, this value determines the stopping method to
apply to the motor. Each supported Stopping Action initiates the associated Stopping
Sequence (IEC60204-1 Category Stops 0, 1, and 2). If the connection is closed intentionally
using a Forward Close service, the selected stopping method is applied while in the Stopping
state and the final state after the stopping method completes is the Initializing state. If
the connection is unintentionally lost and the resulting Node Fault generated (Node Fault
Codes 1 or 6), the selected stopping method is applied while in the Aborting state and the
final state after the stopping method completes is the Major Faulted state. In either final
state the device’s inverter power structure will either be Disabled (Disable selection) and
free of torque or actively held (Hold selection) in a static condition.
Stopping Action Enumeration Definitions
Enum. | Usage | Name | Description |
|---|---|---|---|
0 | R/XD | Disable and Coast | Disable and Coast immediately disables the device power structure and active
control loops, which causes the motor to coast unless some form of external
braking is applied. This is equivalent to an IEC-60204-1 Category 0 Stop. |
1 | R/C O/XF | Current Decel and Disable | Current Decel and Disable leaves the power structure and any active control loops
enabled while stopping. If configured for position control mode, the drive forces the position reference
to hold its current value until the axis reaches zero speed. Once at zero speed
the position reference is immediately set equal to the actual position to hold the
axis at standstill. If in velocity control mode, the drive forces the velocity reference to zero. In either case, forcing the position or velocity reference signals to a fixed
value results in a rapid increase in control loop error of the moving axis that
saturates the output current of the drive to the configured Stopping Torque that
brings the motor to a stop. In torque control mode, the drive directly applies the configured Stopping Torque
to the torque command signal to decelerate the motor. When the velocity feedback
value reaches zero speed, the torque command is set to zero. Once stopped, or the configured Stopping Time or factory time limit expires, the
drive disables the power structure and control loops. This stop mode complies with
the IEC-60204-1 Category 1 Stop. In frequency control mode the operative current limit, rather than the Stopping
Torque attribute, is used to regulate the stopping current. When applied to track sections, this stopping action leaves the power structure
enabled for the configured Stopping Time and Mechanical Brake Engage Delay to
allow time for movers local to the section to be brought to a stop by their
associated remotes sections. |
2 | O/FV | Ramped Decel and Disable | Ramped Decel and Disable also leaves the power structure and any active control
loops enabled while stopping but uses the Ramp Generator associated with the
Velocity Fine Command Generator block to decelerate the motor to a stop. When
initiating a Ramped Decel and Disable Stop, the Ramp Generator is immediately
activated and the drive no longer follows command from the controller. The Ramp
Generator input is initialized to zero and the output is initialized to the
current speed of the motor, thus causing the Ramp Generator output to ramp the
motor from its current speed down to zero according to the ramp control
parameters. Once stopped, or the configured Stopping Time or factory timeout limit
expires, the device disables the power structure and control loops. This stop mode
also complies with the IEC-60204-1 Category 1 Stop. |
3 | O/PV | Current Decel and Hold | Current Decel and Hold behaves like Current Decel and Disable, but leaves the
power structure active with holding torque to maintain the stopped condition. The
method for generating holding torque is left to the drive vendor's discretion.
This stop mode complies with the IEC-60204-1 Category 2 Stop. The Current Decel and Hold stopping action is not allowed if a Start Inhibit
condition is present. If a Start Inhibit condition is present, a Current Decel and
Disable will be initiated instead. |
4 | O/V | Ramped Decel and Hold | Ramped Decel and Hold behaves like Ramped Decel and Disable, but leaves the power
structure with holding torque to maintain the stopped condition. This stop modes
also complies with the IEC-60204-1 Category 2 Stop. The Ramped Decel and Hold stopping action is not allowed if a Start Inhibit
condition is present. If a Start Inhibit condition is present, a Ramped Decel and
Disable will be initiated instead. |
5-127 | Reserved | ||
128-255 | Vendor Specific | ||
128 | O/D | DC Injection Brake | DC Injection Brake immediately applies the configured DC Injection Brake Current
to the motor to create a static flux field to bring the motor to a stop before
disabling the power structure. |
129 | O/D | AC Injection Brake | AC Injection Brake decreases the device output frequency according from its
present value to zero at the rate determined by the configured Deceleration Limit.
Stopping action is accomplished by lowering the output frequency below the motor
rotor speed where regeneration does not occur and instead mechanical energy is
dissipated in the motor as heat. |
Stopping Torque
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Required - C | Set/SSV | REAL | 100 FD | 0 | 10 3 | % Motor Rated |
When disabling or aborting an axis, this value determines the maximum amount of torque
producing current available to stop the motor when the Stopping Action is set to Current
Decel. If this attribute is not supported, the drive device will use the configured Positive
and Negative Peak Current Limits.
Stopping Time Limit
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - XD | Set/SSV | REAL | 1 | 0 | 10 3 | Seconds |
When disabling or aborting an axis, this parameter determines the maximum amount of time
the drive allows to reach zero speed as part of the Category 1 or Category 2 Stop sequence.
Action taken by the drive once the time limit is reached depends on the Stop Category. For a
Category 1 Stop, the drive continues to apply Stopping Torque while engaging the brake. For
a Category 2 Stop the drive continues to apply Stopping Torque but does not engage the
brake. If Stopping Time Limit is not supported a factory set timeout may be applied.
Coasting Time Limit
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - XD | Set/SSV | REAL | Eq 23 0 | 0 | 10 3 | Seconds |
When disabling or aborting an axis, this parameter determines the maximum amount of time
the drive allows to reach zero speed as part of the Category 0 "Disable and Coast" Stop
sequence. Action taken by the drive if the time limit is reached is to engage the brake and
advance to the Stopped state. If this attribute is not supported, the Coasting Time Limit
applies the Stopping Time Limit value. If Stopping Time Limit is not supported a factory set
timeout may be applied.
Resistive Brake Contact Delay
When an external resistive brake is used, an external contactor switches the UVW motor
leads from the inverter power structure to an energy dissipating resistor to stop the motor.
This switching does not occur instantaneously and enabling the power structure too early can
cause electrical arcing across the contactor. To prevent this condition, the Resistive Brake
Contact Delay can be set to the maximum time that it takes to fully close the contactor
across the UVW motor lines so when the axis is enabled, the inverter power structure is not
enabled until after the Resistive Brake Contact Delay Time has expired. Resistive Brake
operation is only applicable to PM Motor types.
The following sequence further defines how the Resistive Brake Contact Delay factors into
the overall Enable Sequence that may also include the operation of a Mechanical Brake. Note
that the Resistive Brake Contact Delay and the Mechanics Brake Release Delay attributes
apply even if there is no external contactor or mechanical brake connected to the drive.
Enable Sequence:
- Switch to Starting state.
- Activate Resistive Brake contactor to connect motor to inverter power structure.
- Wait for "Resistive Brake Contact Delay" while Resistive Brake contacts close.
- Enable inverter power structure.
- (Optional) Perform Torque Proving operation to verify motor control of load.
- Activate Mechanical Brake output to release brake.
- Wait for "Mechanical Brake Release Delay" while brake releases.
- Transition to Running state.
Mechanical Brake Control
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - D | Set/SSV | USINT | 0 | - | - | Enumeration 0 = Automatic 1 = Brake Release 2-225 = Reserved |
The Mechanical Brake Control attribute governs the operation of the Mechanical Brake Output
of the drive. The Mechanical Brake Output controls the mechanical brake mechanism. When set
to Automatic, the Mechanical Brake is under the control of the axis state machine. The
Mechanical Brake Engage Delay and Mechanical Brake Release Delay attributes describe the
sequencing for the brake. To release the brake, set the brake to Brake Release. The axis
state machine releases control of the brake.
Mechanical Brake Release Delay
When enabling the axis with an engaged mechanical brake, the Mechanical Brake Release Delay
value determines the amount of time the drive shall delay transition from the Starting state
to the Running or Testing states. This delay prevents any commanded motion until the
external mechanical brake has had enough time to disengage. If supported, a Torque Proving
operation is included in this sequence prior to releasing the brake. Note that the Resistive
Brake Contact Delay and the Mechanical Brake Release Delay attributes apply even if there is
no external contactor or mechanical brake connected to the drive.
Enable Sequence:
- Switch to Starting state.
- Activate Resistive Brake contactor to connect motor to inverter power structure.
- Wait for "Resistive Brake Contact Delay" while Resistive Brake contacts close.
- Enable inverter power structure.
- (Optional) Perform Torque Proving operation to verify motor control of load.
- Activate Mechanical Brake output to release brake.
- Wait for "Mechanical Brake Release Delay" while brake releases.
- Transition to Running (or Testing) state.
Mechanical Brake Release Current
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - XD | Set/GSV | REAL | 0 DB | 0 | | Amps |
The Mechanical Brake Release Current attribute determines the behavior of the Mechanical
Brake Output when current regulation is supported on the Mechanical Brake Output. Current
regulation on the Mechanical Brake Output can reduce steady-state control power draw when
the current necessary to hold the mechanical brake in the released condition is less than
the current drawn by the mechanical brake when rated voltage is applied.
When the Mechanical Brake Output is released during the Enable sequence, the Mechanical
Brake Output will initially apply maximum output voltage to ensure the Mechanical Brake
properly releases. After a vendor-specific time, the Mechanical Brake Output will switch to
current regulation mode and regulate the output current to the Mechanical Brake Release
Current attribute value. The transition from voltage to current mode is independent from the
value of the Mechanical Brake Release Delay attribute.
A value of zero for the Mechanical Brake Release Current will disable the current
regulation feature of the Mechanical Brake Output and will result in maximum output voltage
while the Mechanical Brake Output is released. This setting is useful for Mechanical Brakes
where the release current is unknown.
Mechanical Brake Engage Delay
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - XD | Set/SSV | REAL | Eq 23 0 | 0 | 10 3 | Seconds |
When disabling the motion axis using a Category 1 Stopping Action, the Mechanical Brake
Engage Delay value determines the amount of time the device power structure will remain
enabled after the axis has decelerated to standstill. This attribute allows time for an
external mechanical brake to engage. The configured Stopping Action determines the type of
stopping sequence applied. If supported, a Brake Proving operation is included in the
Category 1 stopping sequence prior to disabling the power structure. Note that the
Mechanical Brake Release Delay attribute applies even if there is mechanical brake connected
to the drive.
Zero Speed
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - D | Set/SSV | REAL | 1 FD | 0 | | % Motor Rated |
This attribute sets the speed threshold associated with the zero speed criteria of the stop
sequence. Zero Speed is specified as a percent of motor rated speed. When Zero Speed Time
attribute is supported, this attribute sets the speed threshold where the zero speed timer
starts. When the axis speed has been below the Zero Speed threshold for Zero Speed Time the
axis has satisfied the zero speed criteria. In all but Category 2 stops, this results in
action to engage the mechanical brake. If this attribute is not supported, the zero speed
threshold is left to the vendor’s discretion and typically set to 1% of motor rated speed.
Axis speed in the above description is based on the Velocity Feedback signal, or in the case
of a Frequency Control drive, axis speed is based on Velocity Reference signal.
When supporting a Load Observer, the zero speed criteria is not based on the Velocity
Estimate since that signal can differ considerably from the actual speed of the motor. When
the Load Observer is configured to apply the Velocity Estimate to the velocity loop summing
junction as Velocity Feedback, the zero speed criteria must be based on the velocity
feedback signal input to the Load Observer.
Zero Speed Time
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - D | Set/SSV | REAL | 0 | 0 | 10 3 | Sec |
This attribute sets the amount of time that the axis speed must be below the zero speed
threshold, set by the Zero Speed attribute or established by the drive vendor, before
satisfying the zero speed criteria. In all but Category 2 stops, when this attribute is set
it results in action to engage the mechanical brake. If this attribute is not supported, the
amount of time needed to satisfy the zero speed criteria is left to the vendor’s discretion
and typically is immediate (0). Axis speed in the above description is based on the Velocity
Feedback signal, or in the case of a Frequency Control drive, axis speed is based on
Velocity Reference signal.
When supporting a Load Observer, the zero speed criteria is not based on the Velocity
Estimate since that signal can differ considerably from the actual speed of the motor. When
the Load Observer is configured to apply the Velocity Estimate to the velocity loop summing
junction as Velocity Feedback, the zero speed criteria must be based on the velocity
feedback signal input to the Load Observer.
Vertical Load Control
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - FPV | Set/GSV | USINT | 0 | - | - | Enumeration: 0 = Disabled 1 = Enabled 2 - 255 = Reserved |
This enumerated value allows the drive to tailor motor control behavior for vertical load
applications. When the Enabled enumeration is selected, the drive attempts, whenever
possible, to avoid applying Category 0 stop actions in response to Major Fault conditions.
The drive may tailor other aspects of its behavior to best handle vertical loads.
Proving Configuration
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - D | Set/SSV | USINT | 0 FD | - | - | Enumeration: 0 = Disabled 1 = Enabled 2 - 255 = Reserved |
This attribute enables the operation of the drive's Torque Proving and Brake Proving
functions that work in conjunction with mechanical brake control. When Proving is enabled,
the mechanical brake must be set as soon as the drive is disabled. When the brake is under
the control of the axis state machine this is automatic. But when controlled externally,
failure to set the brake when the drive is disabled can cause a free fall condition on a
vertical application.
When enabled, the drive performs a Torque Prove test of the motor current while in the
Starting state to "prove" that current is properly flowing through each of the motor phases
before releasing the brake. Should the Torque Prove test fail, a Motor Phase Loss exception
is generated.
Some test services prohibit running the Torque Prove test (including the Brake Test) during
the Starting State. Torque Proving is bypassed during the enable sequence for these test
services.
While Torque Proving functionality is applicable to drive Control Modes that are not
capable of generating reliable holding torque based on a feedback device, such as Frequency
Control and Sensorless Velocity Control, Torque Proving should not be used in these modes
for applications where holding torque is critical to safe operation, such as in a typical
lift or crane application.
If the optional Brake Test Torque attribute is supported, the Torque Prove test also
includes a proactive Brake Test to ensure the mechanical brake is functioning properly.
Should the Brake Test detect brake slip, a Brake Slip exception is generated.
When Proving is enabled, the drive also performs a Brake Prove test while in the Stopping
or Aborting states to "prove" proper mechanical brake function before the drive power
structure is disabled. Should the Brake Prove test detect brake slip a Brake Slip exception
is generated.
Unless another vendor specific method is used to address a Brake Slip condition in the
Stopping or Aborting state, the appropriate Fault Action for the Brake Slip exception is
Torque Limited Stop and Hold. This Fault Action applies holding torque to arrest the brake
slip and transitions the axis to the Major Faulted state.
In general, Brake Proving functionality is only applicable to drive Control Modes that are
capable of generating holding torque based on a feedback device. Brake Proving is therefore
not applicable to Frequency Control or Sensorless Velocity Control modes.
When Proving is enabled, and the Auto-Sag feature is supported, upon detection of a brake
slip condition, the drive has the capability of safely lowering the load to the ground in a
controlled series of increments. The Auto Sag Configuration attribute is used to enable this
feature. In addition to Brake Slip initiating a Brake Slip exception, the drive also
generates a Brake Malfunction start inhibit when the Auto Sag feature is enabled.
When Proving, Auto Sag, and Auto Sag Start are all enabled, the drive also monitors for
brake slip in the Stopped or Faulted states. If brake slip is detected, the drive power
structure is automatically started to arrest the slip allowing the Auto Sag function to
safely lower the load to the ground. Upon detection of brake slip, a Brake Slip exception is
generated along with a Brake Malfunction start inhibit.
The sequencing of the torque and brake "prove" tests are described in detail by the
Mechanical Brake Engage Delay and Mechanical Brake Release Delay attributes.
The Proving feature includes a number of optional Sub-Features, many of which depend on
support of other Proving feature attributes. The following table defines these attribute
dependencies.
Proving Sub-Feature | Controlling Attributes | Attribute Prerequisites |
|---|---|---|
Torque Prove | Torque Prove Current | Proving Configuration |
Brake Test | Brake Test Torque Brake Slip Tolerance | Proving Configuration |
Brake Prove | Brake Prove Ramp Time Brake Slip Tolerance | Proving Configuration |
Auto Sag | Auto Sag Configuration Auto Sag Slip Increment | Proving Configuration Brake Prove Ramp Time Brake Slip Tolerance |
Auto Sag Start | Auto Sag Start | Proving Configuration Brake Prove Ramp Time Brake Slip Tolerance Auto Sag Configuration Auto Sag Slip Tolerance |
Proving tests are performed when enabling or disabling the drive axis. During these state
transitions a series of operations are performed by the drive to ensure the proper function
of the motor (Torque Proving) and the brake (Brake Proving).
Torque Prove Current
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - D | Set/SSV | REAL | 0 FD | 0 | 10 3 | % Motor Rated |
This attribute sets the percent of motor rated torque applied to the motor by the Torque
Prove test as part of the Torque Proving function executed in the Starting state. The Torque
Prove test applies current to the motor to "prove" that current is properly flowing through
each of the motor phases before releasing the brake.
Brake Test Torque
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - DE | Set/SSV | REAL | 0 FD | 0 | 10 3 | % Motor Rated |
This attribute sets the percent of motor rated torque applied to the motor by the Brake
Test as part of the Torque Proving function executed in the Starting state. This Brake Test
proactively tests the ability of the mechanical brake to hold the maximum anticipated load
before releasing the brake and allowing operation. Should the Brake Test detect brake slip,
a Brake Slip exception is generated.
If the Brake Test Torque attribute value is 0 the Brake Test is not performed in the
Starting state. Some test services prohibit running the Brake Test during the Starting
State. The Brake Test is bypassed during the enable sequence for these test services.
Brake Prove Ramp Time
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - DE | Set/SSV | REAL | 0 FD | 0 | 10 3 | Seconds |
This attribute determines the amount of time the drive will take to ramp the applied torque
of the motor down to zero during the Brake Proving test in the Stopping or Aborting state.
The Brake Prove Ramp Time determines the ramp down rate of the applied torque output by
dividing the Torque Limit by the Brake Prove Ramp Time. The Torque Limit in this case is the
maximum of the configured Torque Limit Positive and Torque Limit Negative values. The Brake
Prove test is performed to check for brake slip before the power structure is disabled.
Brake Slip Tolerance
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - DE | Set/SSV | REAL | 0 FD | 0 | | Position Units |
This attribute determines the amount of brake slip allowed after the brake is engaged. If
this tolerance is exceeded while the brake is engaged, a Brake Slip exception is generated.
Brake slip can therefore be monitored in any axis state where the brake is engaged.
DC Injection Brake Current
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - D | Set/SSV | REAL | 0 | 0 | 10 3 | % Motor Rated |
The DC Injection Brake Current attribute defines the brake current level injected into an
induction motor stator when DC Injection Brake is selected as the Stopping Action. This
attribute is specified as a percent of motor rated speed.
DC Injection Brake Time
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - D | Set/SSV | REAL | 0 | 0 | 10 3 | Seconds |
The DC Injection Brake Time attribute defines the amount of time that the DC brake current
is injected into an induction motor stator when DC Injection Brake is selected as the
Stopping Action. This attribute is specified in seconds.
Flux Braking Enable
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - D (IM) | Set/SSV | USINT | 0 | - | - | 0 = Flux Braking Disabled 1 = Flux Braking Enabled |
The Flux Braking Enable attribute value determines if the drive device is to apply
additional flux current to the induction motor in an effort to increase motor losses and
reduce the deceleration time while in the Stopping state. This feature is useful when there
is no Shunt Regulator or Regenerative Brake available.
Auto Sag Configuration
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - DE | Set/SSV | USINT | 0 | - | - | Enumeration: 0 = Disabled 1 = Enabled 2-255 = (reserved) |
This attribute is used to enable the optional Auto Sag feature that, in the event of
detected a brake slip condition, safely lowers the load to the floor in a series of
controlled Auto Sag Slip Increments. When a brake slip condition is detected and Auto Sag is
enabled, the drive not only sets the standard Brake Slip exception, but the drive also sets
the Brake Malfunction start inhibit. This prevents the drive from restarting after the load
has been safely lowered to the floor.
Auto Sag is incompatible with the Safe Load Retention (SLR) Safety Limit function. Auto Sag
cannot be enabled if SLR Mode is non-zero based on the SLR Mode bit (bit 2) in the Axis
Safety Status – RA attribute being set. Attempting to set Auto Sag Configuration to Enabled
shall result in a Device State Conflict error (General Status error code 0x10).
Auto Sag Slip Increment
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - DE | Set/SSV | REAL | 0 | 0 | | Position Units |
This attribute sets the incremental amount of brake slip allowed by the drive's optional
Auto Sag function before restoring holding torque. When brake slip occurs, the drive allows
this amount of displacement and then automatically enables the power structure and applies
holding torque to arrest the slip. The drive then ramps the motor torque to zero based on
the Brake Prove Ramp Time while checking for slip. Should brake slip continue, the cycle
repeats. In crane and lift applications, this repeating "Auto Sag" cycle is designed to
lower the load in a controlled series of Auto Sag Slip Increments until the load reaches the
ground.
Auto Sag Time Limit
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - DE | Set/SSV | REAL | 0.25 | 0 | | Seconds |
This attribute sets the time limit over which the drive checks for brake slip as performed
by the Auto Sag function before restoring holding torque. When brake slip occurs, the drive
allows this amount of time before automatically enabling the power structure and applying
holding torque. The drive then ramps the motor torque to zero based on the Brake Prove Ramp
Time while checking for slip. Generally, in a brake slip situation, the Auto Sag Slip Time
Limit expires when the load reaches the ground after one or more Auto Sag Slip Increment
cycles. With no further slip occurring while the motor torque is ramping to zero, the Auto
Sag feature transitions the axis to the Major Faulted state and the drive power structure is
disabled.
The optional Auto Sag Slip Time Limit attribute is not required by the Auto Sag feature. If
not supported, a vendor specific value for the Auto Sag Slip Time is applied, typically 0.25
seconds.
Auto Sag Start
Usage | Access | Data Type | Default | Min | Max | Semantics of Values |
|---|---|---|---|---|---|---|
Optional - DE | Set/SSV | USINT | 0 | - | - | Enumeration: 0 = Disabled 1 = Enabled 2-255 = (reserved) |
When the Auto Sag Configuration attribute is set to Enabled, this attribute is used to
enable the Auto Sag function in the Stopped or Faulted state. When Auto Sag Start is
enabled, the drive monitors the load for possible brake slip and should the amount of brake
slip exceed the Brake Slip Tolerance a Brake Slip exception is generated, along with a Brake
Malfunction start inhibit. When this occurs, the drive power structure is enabled (Started)
without holding torque and the axis transitions to the Aborting State. The drive continues
to monitor brake slip and when the amount of slip exceeds the Auto Sag Slip Increment
holding torque is applied to the motor to arrest the brake slip. The drive then ramps the
motor torque to zero based on the Brake Prove Ramp Time while again checking for slip.
Should brake slip continue and exceed the Auto Sag Slip Increment, holding torque is applied
and the cycle repeats. In crane and lift applications, this repeating "Auto Sag" cycle is
designed to lower the load in a controlled series of Auto Sag Slip Increments until the load
reaches the ground.
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