| 1) Which is the difference between practiSPIN™ and powerSPIN™? |
powerSPIN™ is a family of motor driver ICs; practiSPIN™ is an evaluation tool developed for the powerSPIN family drivers plus other driver ICs.
| 2) How can I get a practiSPIN™ system? |
You can order the system by contacting your ST salesman or a franchised ST distributor.
| 3) Is practiSPIN™ a real-time evaluation tool? |
The practiSPIN™ software provided with the tool is actually made up of two different tools in the same package.
The first tool is an interface between the personal computer and the motor driver. This section can drive in real-time different kind of motors.
The software also includes a power dissipation and thermal analysis section, that is not real-time but helps in calculating the IC power dissipation and estimating its junction temperature, through a simulation.
| 4) What type of thermal simulation can be performed? |
The software performs three kinds of simulations.
A steady state simulation, so assuming that the motor is always running with the same current.
A single pulse analysis, in which the motor accelerates for a certain amount of time at a certain current, then runs with a different current value for a fixed time, then stops. The result of the simulation is the maximum temperature reached by the IC junction.
Last, the repeated pulse analysis, in which the motor executes cycles of running and waiting.
| 5) Can the practiSPIN™ drive a stepper motor in microstepping mode? |
Yes, software provided with practiSPIN™ allows running stepper motors in microstepping mode using the L6208 with 16 microsteps per step. You need two DAC to implement microstepping. In the practiSPIN™ system, two PWM outputs from the ST72264 are used as a simple DAC by filtering the output and applying that voltage to the Vref pins of the L6208.
| 6) What is the maximum power output from the practiSPIN™ system? |
That obviously depends on which device you are using. As with most power devices, the maximum output current is limited by the dissipation, not the maximum rating of the device. For a typical application using the L6208PD, the device can deliver in the range of 1.75 A continuously in both bridges. With a 48V rated motor, you are looking at about 150 W total output.
| 7) Can I get a higher resolution microstepping than the 16 microsteps per step that you discussed? |
Yes, using the same hardware and changing only the software we can increase the resolution to 64 microsteps per step. This is achievable using a 8 bit PWM. To go beyond 64 microsteps you need a DAC or PWM output with a larger resolution.
| 8) Which devices are supported by the practiSPIN™ system? |
A list of the supported devices and the applications types supported for each device is available on the web site at the URL shown. At this time they include the L6205 L6206 L6207 L6208 L6235 L6225 L6226 L6227 L6228 L6229 L6258 PBL3717 TEA3717 Tea3718 and the L6219.
| 9) Is there an evaluation board for the L6228? |
Yes. The devices of the L622x family are functionally the same and pin compatible with the L620x family of devices so you can use the evaluation board for the L6208. The main difference is the Rdson of the device, so your first evaluation can be done with the board as it comes from ST, eventually replacing the L6208 IC with the L6228.
| 10) Does the practiSPIN™ system create the code for the microcontroller? |
No, the system is designed to evaluate the driver ICs, not as a development system for the microcontroller. There will be an application note available shortly that describes algorithm used in the demo.
| 11) Can the practiSPIN™ drive 4 DC motors? |
The devices may drive 4 DC motors without direction control. However the software in the practiSPIN™ does not support this mode of operation.
| 12) Can I run the L6208 with just an oscillator? |
Generally no. Although the L6208 could be run with just an oscillator for the clock input, you can't run most motors that way. You could only run it with a fixed oscillator if that running speed were below the speed torque curve of the motor. Most stepper systems are not designed that way. That's why we suggested the trapezoidal movement profile.
| 13) What is the difference between the current control and the current limit function? |
The current control sense across the sense resistor and is intended to provide a regulated current. The over current detection senses the current on the high side and is intended to provide protection against shorted loads or shorts on the output to ground.
| 14) Can two stepper motors be driven by the practiSPIN™? |
No. Since a typical bipolar steeper requires two H-Bridges to drive it, the system only drives one stepper motor. |
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