Amplifier - Twang Reference Parameters

ID Label Type #Val Min Max Attr Description

10727

Twang-ref duration for twang ON, sec

Flt32

 

0.01

 

Amount of time in seconds to allow the motor to be energized during the twang process.

10728

Twang-ref duration for twang OFF, sec

Flt32

 

0.01

 

Amount of time in seconds to let the motor be de-energized before wrapping up the twang-ref operation.

10729

Twang-ref delay time to release brake, sec

Flt32

 

0.01

10 

 

After a twang is applied, this is the time delay in seconds before the brake is released.

10730

Twang-ref delay time to engage brake, sec

Flt32

 

 0.01

10

 

When the twang is active, the motor is effectively locked on a single phase.  When this occurs, the brake is re-engaged.  After the brake is engaged, the system waits the time specified by this parameter before un-twanging (de-energizing) the motor.  This delay allows the brakes to fully engage.

10731

# of ramp steps to a twang

Int16

 

 

 

 

# of steps to ramp to a target twang torque and angle. The default # of steps is 5. In this case, to reach a target twang it takes a total of 5 twangs. This allows the user to minimize the amount of disturbance induced by the twang-ref process.

10732

# of twang-ref checks

Uint8

 

 

 

 

# of intermediate twang-ref checks. After the motor is initially twanged to the commutation reference position the servo will optionally commence additional twangs to different offset angles to make sure that the first twang reached the commutation reference position correctly. The default # of twang checks is 2. Setting this value to 0 would cause the system to skip the twang-ref check altogether.

Possible reasons for failing the twang-ref check are:

   - The motor is leaning against a hardstop and it's trying to twang into it.
   - Too much axis friction and too small a twang torque.

10733

Twang-ref check duration time, sec

Flt32

 

0.01

5

 

After each twang check process, this is the delay time in seconds for the axis to settle before the twang position is read. The twang position is compared to the initial twang-reference position to calculate a delta count. It is then converted into a delta angle, and checked against the commanded twang angle. The difference must fall within a preset percentage limit (DataID 10734) in order to pass the check.

10734

Twang-ref check position tolerance limit, %

Flt32

 

 0

40

 

Maximum allowed twang angle check deviation percentage. See DataID 10733.

10735

Twang-reference torque %

%

 

 

 

 

Torque used during the twang reference operation (also see "Twang-ref angle, degree" DataID 10726). This value and the ref angle are supplied to a voltage twang command, which energizes the motor. After the motor "locks" into the twang angle, it establishes the commutation reference position.

This torque is defined as a % of the "RMS rated motor torque, tcnt" (DataID 10612). By default, this value is set to 100%.