DMC Sigma2N - Page 43

Simga2N Traction Advanced Manual– V1.3 Page 43 (166) ©2021 DMC GmbH Herten Germany
• If set to 0 (Fixed), the direction braking ramp time (i.e. deceleration rate in direction braking) is as set
by the parameter “M1.1-7 Direction brake ramp time “DBrkRamp””, regardless of Accelerator
potentiometer position.
• If set to 1 (Proportional), the direction braking ramp time depends on the Accelerator potentiometer
position. At the minimum Accelerator potentiometer position, the direction braking ramp time will be
as set by the parameter “M1.1-4 Neutral brake ramp time “NBrkRamp””, while at the maximum
Accelerator potentiometer position the braking ramp will be as set by the parameter, “M1.1-7
Direction brake ramp time “DBrkRamp””. Between minimum and maximum, the braking strength is a
value between the neutral and direction braking settings, proportional to the Accelerator
potentiometer position.
M1.1-6 Direction brake torque “DBrake”
This parameter is active only in torque mode.
This sets the strength of the braking upon a direction change, i.e. form forward to reverse.
The setting is a percentage of maximum motor torque. The maximum motor torque is defined by “Maximum
motor current” (adjustable in “Menu 3 “Autotuning””), assumed to be 100% of torque.
M1.1-7 Direction brake ramp time “DBrkRamp”
In Torque Control mode this sets the time taken to ramp from no braking torque to full braking torque, upon a
change of direction. Increasing the value gives a smoother but longer transition from drive to direction braking.
In Speed Control mode this sets the time taken to ramp down the speed in the current direction form 100% to
zero (0%) or from the active speed limit to 0% (depending on “M2-13 Variable/Constant ramp time
“CnRmpTm””), upon a change of direction. After passing through zero speed, the normal acceleration time as
described in “M1.1-1 Accelerator ramp time “Acc Ramp”” is applied. Increasing the value gives a smoother but
longer transition to zero speed.
NOTICE!
Important for speed control:
When speed control selected (“M2-1 Control Mode “Spd/Torq”” = 0) using a very low value of
time will bring a very harsh direction braking.
M1.1-8 Max. direction braking speed “MxDBrkSp”
This parameter inhibits the change of direction if the speed is above a tunable threshold (between 0% and
100% of the max speed).
The default value for MxDbrkSp is 100%, which means this function is disabled and it is always allowed to
change the direction while vehicle is moving.
If the value is set lower than 100% the details of the different situations will be described as follow:
DIRECTION CHANGE OPERATION (described for motor driving forward with forward direction applied)
I. If the motor speed is below “MxDbrkSp” and reverse direction is selected, the direction change
operation is allowed regardless of the accelerator position;
II. If the motor speed is above “MxDbrSp” and reverse direction is selected, the direction change
operation is always denied, the motor is stopped according to neutral brake settings (“M1.1-4 Neutral
brake ramp time “NBrkRamp””, “M1.1-3 Neutral brake torque “NBrake””) and the controller signals a
fault;
III. If the motor speed is above “MdDbrSp” and neutral is selected, the motor slows down according to
neutral brake settings (“M1.1-4 Neutral brake ramp time “NBrkRamp””, “M1.1-3 Neutral brake torque
“NBrake””). When the speed drops below “MxDbrSp” it is possible to select the reverse direction only
if the accelerator position is 0% (pedal fully released).
IV. If the motor speed is above “MdDbrSp” and the accelerator is released (forward direction still
selected), the motor slows down according to “M1.1-4 Neutral brake ramp time “NBrkRamp””. When
the speed drops below “MxDbrSp” it is possible to select the reverse direction regardless of the
accelerator position.