Simga2N Traction Advanced Manual– V1.3 Page 138 (166) ©2021 DMC GmbH Herten Germany
6 Safety related functions
The Sigma2N motor controller has some safety related functions that can be enable to enhance the application safety.
The following list resumes the main function related to safety.
Speed Guard Function
In applications where speed control is adopted together with EM brake and no mechanical brake is installed, the system
is relying on speed control accuracy for stopping and holding the vehicle until the EM brake is locking it in position.
A function monitoring and tracking how close the motor is in following the speed request can help to prevent issues.
The function is checking whether the actual motor speed is “too far” and for “too long” from the demanded value by
the user. If this happens, a failure is signalled and the EM brake immediately locks the motor. For details refer to “M5.9-
1 Speed control guard tracking error threshold “SpdGrdTH”” and “M5.9-2 Speed control guard timer “SpdGrdTm””.
Thermal cut back applied to Speed Limitation
In applications where speed control is adopted together with EM brake and no mechanical brake is installed, the system
is relying on speed control accuracy for stopping and holding the vehicle until the EM brake is locking it in position.
In those cases a reduction of “torque capability” might create issues. For example, in case of motor overheating or
controller overheating, a drive torque limitation as a function of overtemperature occurs. This torque limitation restricts
the motor capability to follow the speed demand. In applications relying on speed control it is possible to select that in
case of thermal cutback the speed is limited instead of torque. In this way the user immediately realize that something
is not ok. For enabling this function and for details refer to “M2-11 Digital output PWM chopping frequency “DO freq”
This parameter can be used to change the chopping frequency used to lower the voltage applied at the digital outputs.
Use speed limits instead of torque limits “TmpLVSpL””.
Motor Stall function
During vehicle operation it might happen that motor can be stuck and not able to start due to excessive load torque.
Regardless of the fact that torque mode or speed mode is employed, it could happen that the controller is “pushing”
full current in the motor for several seconds and the motor is applying full torque. This can be dangerous for motor
quick overheating and for the mechanical transmission. There is a function that can detect a “motor stall” situation. To
enable it please refer to “M5.8-1 Torque threshold for stall protection “TrqTHLim”” and “M5.8-2 Stall protection timer
“StallTim””.
Motor Feed back wire off and noise detection
Motor speed feedback is a key information for proper motor control. In case of sensor wire off or excessive electrical
noise on feedback signals, the motor must be stopped and an error must be signalled for a proper diagnostic coverage.
For PMS and IPM motor technology the wire off and noise detection is enabled by default. For AC motor technology
please refer to “M5.10-1 Encoder noise detection “EncodND”” and “M5.10-2 Noise detection error threshold “Noise
Err”” for enabling the noise detection function.
Safe Torque Off (STO) and Safe Stop 1 (SS1)
Safe Torque Off (STO) and Safe Stop 1 (SS1) are standard safety functions available in Super Sigma 2 controller. They are
meant to work in conjunction with control via can. For details please refer to [1].
Prevent driving
For vehicle application at power on the “prevent driving function” is mandatory for safety. A sort of enable driving input
is available for all type of vehicle options. See description of input “Pin A4 Seat / Tiller / Safe torque off”.
Potentiometers supply wire off detection
Is it possible to enable function to detect the wire off of potentiometer supply up to two potentiometers for accelerator
of footbrake pedal and/or for steer pot input. For detailed information refer to “M2-6 Accelerator supply wire off
detection ”SplyWrOf”” and section 3.1.3 Wiring of analog inputs.
To Next Page
Loading...
