Control modes General The control mode of systems without feedback is called open loop, the mode with feedback is called closed loop. In the closed loop control mode, it is initially irrelevant whether the fed back signals come from the motor itself or from the influenced process. For controllers with feedback, the measured control variable (actual value) is constantly compared with a set point (set value). In the event of deviations between these values, the controller readjusts according to the specified control parameters. Pure controllers, on the other hand, have no feedback for the value that is to be regulated. The set point (set value) is only specified. Due to a lack of feedback, the closed loop control mode is not possible with the C5. Open-Loop Introduction Open-loop mode is only used with stepper motors and is, by definition, a control mode without feedback. The field rotation in the stator is specified by the controller. The rotor directly follows the magnetic field rotation without step losses as long as no limit parameters, such as the maximum possible torque, are exceeded. Compared to closed-loop, no complex internal control processes are needed in the controller. As a result, the requirements on the controller hardware and the controller logic are very low. Open-loop mode is used primarily with price-sensitive applications and simple movement tasks. Because, unlike closed-loop, there is no feedback for the current rotor position, no conclusion can be drawn on the counter torque being applied to the output side of the motor shaft. To compensate for any torque fluctuations that arise on the output shaft of the motor, in open-loop mode, the controller always supplies the maximum possible (e.g., specified by parameters) set current to the stator windings over the entire speed range. The high magnetic field strength thereby produced forces the rotor to assume the new steady state in a very short time. This torque is, however, opposite that of the inertia of the rotor and overall system. Under certain operating conditions, this combination is prone to resonances, comparable to a spring-mass system. Commissioning To use open-loop mode, the following settings are necessary: In object 2030h (Pole Pair Count), enter the number of pole pairs (see motor data sheet: for a stepper motor with 2 phases, a step angle of 1.8° corresponds to 50 pole pairs and 0.9° corresponds to 100 pole pairs). In object 2031h:00h, enter the maximum permissible motor current (motor protection) in mA (see motor data sheet) In object 6075h:00h, enter the rated current of the motor in mA (see motor data sheet). In object 6073h:00h, enter the maximum current (for a stepper motor, generally corresponds to the rated current, bipolar) in tenths of a percent of the set rated current (see motor data sheet). Factory settings: "1000", which corresponds to 100% of the value in 6073h. A value greater than "1000" is limited internally to "1000". In object 3202h (Motor Drive Submode Select), set bit 0 (CL/OL) to the value "0". Nanotec recommends to activate the current reduction on motor standstill in order to reduce the power loss and heat build-up. To activate current reduction, the following settings are necessary: In object 3202h (Motor Drive Submode Select), set bit 3 (CurRed) to "1". In object 2036h (open-loop current reduction idle time), the time in milliseconds is specified that the motor must be at a standstill (set value is checked) before current reduction is activated. In object 2037h (open-loop current reduction value/factor), the root mean square is specified to which the rated current is to be reduced if current reduction is activated in open loop and the motor is at a standstill. Optimizations Depending on the system, resonances may occur in open-loop mode; susceptibility to resonances is particularly high at low loads. Practical experience has shown that, depending on the application, various measures are effective for largely reducing resonances: Reduce or increase current, see objects 6073h and 6075h, respectively. An excessive torque reserve promotes resonances. Reduce or increase the operating voltage, taking into account the product-specific ranges (with sufficient torque reserve). The permissible operating voltage range can be found in the product data sheet. Optimize the control parameters of the current controller via objects 3210h:09h (I_P) and 3210h:0Ah (I_I) (generally not necessary). Adjustments to the acceleration, deceleration and/or target speed depending on the selected control mode: Profile Position operating mode Objects 6083h (Profile Acceleration), 6084h (Profile Deceleration) and 6081h (Profile Velocity). Velocity operating mode Objects 6048h (Velocity Acceleration), 6049h (Velocity Deceleration) and 6042h (Target Velocity). Profile Velocity operating mode Objects 6083h (Profile Acceleration), 6084h (Profile Deceleration) and 6081h (Profile Velocity). Homing operating mode Objects 609Ah (Homing Acceleration), 6099h:01h (Speed During Search For Switch) and 6099h:02h (Speed During Search For Zero). Interpolated Position Mode operating mode The acceleration and deceleration ramps can be influenced with the higher-level controller. Cyclic Synchronous Position operating mode The acceleration and deceleration ramps can be influenced via the external "position specification / time unit" targets. Cyclic Synchronous Velocity operating mode The acceleration and deceleration ramps can be influenced via the external "position specification / time unit" targets. Clock-direction operating mode Change of the step resolution via objects 2057h (Clock Direction Multiplier) and 2058h (Clock Direction Divider). Optimize acceleration / deceleration ramps by adjusting the pulse frequency to pass through the resonance range as quickly as possible.
Control modes General The control mode of systems without feedback is called open loop, the mode with feedback is called closed loop. In the closed loop control mode, it is initially irrelevant whether the fed back signals come from the motor itself or from the influenced process. For controllers with feedback, the measured control variable (actual value) is constantly compared with a set point (set value). In the event of deviations between these values, the controller readjusts according to the specified control parameters. Pure controllers, on the other hand, have no feedback for the value that is to be regulated. The set point (set value) is only specified. Due to a lack of feedback, the closed loop control mode is not possible with the C5. Open-Loop Introduction Open-loop mode is only used with stepper motors and is, by definition, a control mode without feedback. The field rotation in the stator is specified by the controller. The rotor directly follows the magnetic field rotation without step losses as long as no limit parameters, such as the maximum possible torque, are exceeded. Compared to closed-loop, no complex internal control processes are needed in the controller. As a result, the requirements on the controller hardware and the controller logic are very low. Open-loop mode is used primarily with price-sensitive applications and simple movement tasks. Because, unlike closed-loop, there is no feedback for the current rotor position, no conclusion can be drawn on the counter torque being applied to the output side of the motor shaft. To compensate for any torque fluctuations that arise on the output shaft of the motor, in open-loop mode, the controller always supplies the maximum possible (e.g., specified by parameters) set current to the stator windings over the entire speed range. The high magnetic field strength thereby produced forces the rotor to assume the new steady state in a very short time. This torque is, however, opposite that of the inertia of the rotor and overall system. Under certain operating conditions, this combination is prone to resonances, comparable to a spring-mass system. Commissioning To use open-loop mode, the following settings are necessary: In object 2030h (Pole Pair Count), enter the number of pole pairs (see motor data sheet: for a stepper motor with 2 phases, a step angle of 1.8° corresponds to 50 pole pairs and 0.9° corresponds to 100 pole pairs). In object 2031h:00h, enter the maximum permissible motor current (motor protection) in mA (see motor data sheet) In object 6075h:00h, enter the rated current of the motor in mA (see motor data sheet). In object 6073h:00h, enter the maximum current (for a stepper motor, generally corresponds to the rated current, bipolar) in tenths of a percent of the set rated current (see motor data sheet). Factory settings: "1000", which corresponds to 100% of the value in 6073h. A value greater than "1000" is limited internally to "1000". In object 3202h (Motor Drive Submode Select), set bit 0 (CL/OL) to the value "0". Nanotec recommends to activate the current reduction on motor standstill in order to reduce the power loss and heat build-up. To activate current reduction, the following settings are necessary: In object 3202h (Motor Drive Submode Select), set bit 3 (CurRed) to "1". In object 2036h (open-loop current reduction idle time), the time in milliseconds is specified that the motor must be at a standstill (set value is checked) before current reduction is activated. In object 2037h (open-loop current reduction value/factor), the root mean square is specified to which the rated current is to be reduced if current reduction is activated in open loop and the motor is at a standstill. Optimizations Depending on the system, resonances may occur in open-loop mode; susceptibility to resonances is particularly high at low loads. Practical experience has shown that, depending on the application, various measures are effective for largely reducing resonances: Reduce or increase current, see objects 6073h and 6075h, respectively. An excessive torque reserve promotes resonances. Reduce or increase the operating voltage, taking into account the product-specific ranges (with sufficient torque reserve). The permissible operating voltage range can be found in the product data sheet. Optimize the control parameters of the current controller via objects 3210h:09h (I_P) and 3210h:0Ah (I_I) (generally not necessary). Adjustments to the acceleration, deceleration and/or target speed depending on the selected control mode: Profile Position operating mode Objects 6083h (Profile Acceleration), 6084h (Profile Deceleration) and 6081h (Profile Velocity). Velocity operating mode Objects 6048h (Velocity Acceleration), 6049h (Velocity Deceleration) and 6042h (Target Velocity). Profile Velocity operating mode Objects 6083h (Profile Acceleration), 6084h (Profile Deceleration) and 6081h (Profile Velocity). Homing operating mode Objects 609Ah (Homing Acceleration), 6099h:01h (Speed During Search For Switch) and 6099h:02h (Speed During Search For Zero). Interpolated Position Mode operating mode The acceleration and deceleration ramps can be influenced with the higher-level controller. Cyclic Synchronous Position operating mode The acceleration and deceleration ramps can be influenced via the external "position specification / time unit" targets. Cyclic Synchronous Velocity operating mode The acceleration and deceleration ramps can be influenced via the external "position specification / time unit" targets. Clock-direction operating mode Change of the step resolution via objects 2057h (Clock Direction Multiplier) and 2058h (Clock Direction Divider). Optimize acceleration / deceleration ramps by adjusting the pulse frequency to pass through the resonance range as quickly as possible.
General The control mode of systems without feedback is called open loop, the mode with feedback is called closed loop. In the closed loop control mode, it is initially irrelevant whether the fed back signals come from the motor itself or from the influenced process. For controllers with feedback, the measured control variable (actual value) is constantly compared with a set point (set value). In the event of deviations between these values, the controller readjusts according to the specified control parameters. Pure controllers, on the other hand, have no feedback for the value that is to be regulated. The set point (set value) is only specified. Due to a lack of feedback, the closed loop control mode is not possible with the C5.
Open-Loop Introduction Open-loop mode is only used with stepper motors and is, by definition, a control mode without feedback. The field rotation in the stator is specified by the controller. The rotor directly follows the magnetic field rotation without step losses as long as no limit parameters, such as the maximum possible torque, are exceeded. Compared to closed-loop, no complex internal control processes are needed in the controller. As a result, the requirements on the controller hardware and the controller logic are very low. Open-loop mode is used primarily with price-sensitive applications and simple movement tasks. Because, unlike closed-loop, there is no feedback for the current rotor position, no conclusion can be drawn on the counter torque being applied to the output side of the motor shaft. To compensate for any torque fluctuations that arise on the output shaft of the motor, in open-loop mode, the controller always supplies the maximum possible (e.g., specified by parameters) set current to the stator windings over the entire speed range. The high magnetic field strength thereby produced forces the rotor to assume the new steady state in a very short time. This torque is, however, opposite that of the inertia of the rotor and overall system. Under certain operating conditions, this combination is prone to resonances, comparable to a spring-mass system. Commissioning To use open-loop mode, the following settings are necessary: In object 2030h (Pole Pair Count), enter the number of pole pairs (see motor data sheet: for a stepper motor with 2 phases, a step angle of 1.8° corresponds to 50 pole pairs and 0.9° corresponds to 100 pole pairs). In object 2031h:00h, enter the maximum permissible motor current (motor protection) in mA (see motor data sheet) In object 6075h:00h, enter the rated current of the motor in mA (see motor data sheet). In object 6073h:00h, enter the maximum current (for a stepper motor, generally corresponds to the rated current, bipolar) in tenths of a percent of the set rated current (see motor data sheet). Factory settings: "1000", which corresponds to 100% of the value in 6073h. A value greater than "1000" is limited internally to "1000". In object 3202h (Motor Drive Submode Select), set bit 0 (CL/OL) to the value "0". Nanotec recommends to activate the current reduction on motor standstill in order to reduce the power loss and heat build-up. To activate current reduction, the following settings are necessary: In object 3202h (Motor Drive Submode Select), set bit 3 (CurRed) to "1". In object 2036h (open-loop current reduction idle time), the time in milliseconds is specified that the motor must be at a standstill (set value is checked) before current reduction is activated. In object 2037h (open-loop current reduction value/factor), the root mean square is specified to which the rated current is to be reduced if current reduction is activated in open loop and the motor is at a standstill. Optimizations Depending on the system, resonances may occur in open-loop mode; susceptibility to resonances is particularly high at low loads. Practical experience has shown that, depending on the application, various measures are effective for largely reducing resonances: Reduce or increase current, see objects 6073h and 6075h, respectively. An excessive torque reserve promotes resonances. Reduce or increase the operating voltage, taking into account the product-specific ranges (with sufficient torque reserve). The permissible operating voltage range can be found in the product data sheet. Optimize the control parameters of the current controller via objects 3210h:09h (I_P) and 3210h:0Ah (I_I) (generally not necessary). Adjustments to the acceleration, deceleration and/or target speed depending on the selected control mode: Profile Position operating mode Objects 6083h (Profile Acceleration), 6084h (Profile Deceleration) and 6081h (Profile Velocity). Velocity operating mode Objects 6048h (Velocity Acceleration), 6049h (Velocity Deceleration) and 6042h (Target Velocity). Profile Velocity operating mode Objects 6083h (Profile Acceleration), 6084h (Profile Deceleration) and 6081h (Profile Velocity). Homing operating mode Objects 609Ah (Homing Acceleration), 6099h:01h (Speed During Search For Switch) and 6099h:02h (Speed During Search For Zero). Interpolated Position Mode operating mode The acceleration and deceleration ramps can be influenced with the higher-level controller. Cyclic Synchronous Position operating mode The acceleration and deceleration ramps can be influenced via the external "position specification / time unit" targets. Cyclic Synchronous Velocity operating mode The acceleration and deceleration ramps can be influenced via the external "position specification / time unit" targets. Clock-direction operating mode Change of the step resolution via objects 2057h (Clock Direction Multiplier) and 2058h (Clock Direction Divider). Optimize acceleration / deceleration ramps by adjusting the pulse frequency to pass through the resonance range as quickly as possible.
Introduction Open-loop mode is only used with stepper motors and is, by definition, a control mode without feedback. The field rotation in the stator is specified by the controller. The rotor directly follows the magnetic field rotation without step losses as long as no limit parameters, such as the maximum possible torque, are exceeded. Compared to closed-loop, no complex internal control processes are needed in the controller. As a result, the requirements on the controller hardware and the controller logic are very low. Open-loop mode is used primarily with price-sensitive applications and simple movement tasks. Because, unlike closed-loop, there is no feedback for the current rotor position, no conclusion can be drawn on the counter torque being applied to the output side of the motor shaft. To compensate for any torque fluctuations that arise on the output shaft of the motor, in open-loop mode, the controller always supplies the maximum possible (e.g., specified by parameters) set current to the stator windings over the entire speed range. The high magnetic field strength thereby produced forces the rotor to assume the new steady state in a very short time. This torque is, however, opposite that of the inertia of the rotor and overall system. Under certain operating conditions, this combination is prone to resonances, comparable to a spring-mass system.
Commissioning To use open-loop mode, the following settings are necessary: In object 2030h (Pole Pair Count), enter the number of pole pairs (see motor data sheet: for a stepper motor with 2 phases, a step angle of 1.8° corresponds to 50 pole pairs and 0.9° corresponds to 100 pole pairs). In object 2031h:00h, enter the maximum permissible motor current (motor protection) in mA (see motor data sheet) In object 6075h:00h, enter the rated current of the motor in mA (see motor data sheet). In object 6073h:00h, enter the maximum current (for a stepper motor, generally corresponds to the rated current, bipolar) in tenths of a percent of the set rated current (see motor data sheet). Factory settings: "1000", which corresponds to 100% of the value in 6073h. A value greater than "1000" is limited internally to "1000". In object 3202h (Motor Drive Submode Select), set bit 0 (CL/OL) to the value "0". Nanotec recommends to activate the current reduction on motor standstill in order to reduce the power loss and heat build-up. To activate current reduction, the following settings are necessary: In object 3202h (Motor Drive Submode Select), set bit 3 (CurRed) to "1". In object 2036h (open-loop current reduction idle time), the time in milliseconds is specified that the motor must be at a standstill (set value is checked) before current reduction is activated. In object 2037h (open-loop current reduction value/factor), the root mean square is specified to which the rated current is to be reduced if current reduction is activated in open loop and the motor is at a standstill.
Optimizations Depending on the system, resonances may occur in open-loop mode; susceptibility to resonances is particularly high at low loads. Practical experience has shown that, depending on the application, various measures are effective for largely reducing resonances: Reduce or increase current, see objects 6073h and 6075h, respectively. An excessive torque reserve promotes resonances. Reduce or increase the operating voltage, taking into account the product-specific ranges (with sufficient torque reserve). The permissible operating voltage range can be found in the product data sheet. Optimize the control parameters of the current controller via objects 3210h:09h (I_P) and 3210h:0Ah (I_I) (generally not necessary). Adjustments to the acceleration, deceleration and/or target speed depending on the selected control mode: Profile Position operating mode Objects 6083h (Profile Acceleration), 6084h (Profile Deceleration) and 6081h (Profile Velocity). Velocity operating mode Objects 6048h (Velocity Acceleration), 6049h (Velocity Deceleration) and 6042h (Target Velocity). Profile Velocity operating mode Objects 6083h (Profile Acceleration), 6084h (Profile Deceleration) and 6081h (Profile Velocity). Homing operating mode Objects 609Ah (Homing Acceleration), 6099h:01h (Speed During Search For Switch) and 6099h:02h (Speed During Search For Zero). Interpolated Position Mode operating mode The acceleration and deceleration ramps can be influenced with the higher-level controller. Cyclic Synchronous Position operating mode The acceleration and deceleration ramps can be influenced via the external "position specification / time unit" targets. Cyclic Synchronous Velocity operating mode The acceleration and deceleration ramps can be influenced via the external "position specification / time unit" targets. Clock-direction operating mode Change of the step resolution via objects 2057h (Clock Direction Multiplier) and 2058h (Clock Direction Divider). Optimize acceleration / deceleration ramps by adjusting the pulse frequency to pass through the resonance range as quickly as possible.
