Figure 2.2.1: IMS ISP300 Switch Mode Power Supply

SECTION 2.2

Interfacing DC Power

Choosing a Power Supply for Your MDrive

When choosing a power supply for your MDrivePlus there are performance and sizing issues that must be addressed. An undersized power supply can lead to poor performance and even possible damage to the device, which can be both time consuming and expensive. However, The design of the MDrivePlus is quite efficient and may not re- quire as large a supply as you might suspect.

Motors have windings that are electrically just inductors, and with inductors comes re- sistance and inductance. Winding resistance and inductance result in a L/R time constant that resists the change in current. It requires five time constants to reach nominal current. To effectively manipulate the di/dt or the rate of charge, the voltage applied is increased. When traveling at high speeds there is less time between steps to reach current. The point where the rate of commutation does

not allow the driver to reach full current is referred to as Voltage Mode. Ideally you want to be in Current Mode, which is when the drive is achieving the desired current between steps. Simply stated, a higher voltage will de- crease the time it takes to charge the coil, and therefore will allow for higher torque at higher speeds.

Another characteristic of all motors is Back EMF, and though nothing can be done about back EMF, we can give a path of low impedance by supplying enough output capacitance. Back EMF is a source of current that can push the output of a power supply beyond the maximum operating voltage of the driver and as a result could damage the MDrivePlus over time.

The MDrivePlus is very current efficient as far as the power supply is concerned. Once the motor has charged one or both windings of the motor, all the power supply has to do is replace losses in the system. The charged winding acts as an energy storage in that the current will re-circulate within the bridge, and in and out of each phase reservoir. While one phase is in the decaying stage of the variable chopping oscillator, the other phase is in the charging stage, this results in a less than expected current draw on the supply.

The MDrivePlus is designed with the intention that a user’s power supply output will ramp up to greater or equal to the minimum operating voltage. The initial current surge is quite substantial and could damage the driver if the supply is undersized. If a power supply is undersized, upon a current surge the supply could fall below the operating range of the driver. This could cause the power supply to start oscillating in and out of the voltage range of the driver and result in damaging either the supply, driver or both. There are two types of supplies com- monly used, regulated and unregulated, both of which can be switching or linear. All have their advantages and disadvantages.

An unregulated linear supply is less expensive and more resilient to current surges, however, voltage decreases with increasing current draw. This can cause serious problems if the voltage drops below the working range of the drive. Also of concern is the fluctuations in line voltage. This can cause the unregulated linear supply to be above or below the anticipated voltage.

A regulated supply maintains a stable output voltage, which is good for high speed performance. They are also not bothered by line fluctuations, however, they are more expensive. Depending on the current regulation, a regulated supply may crowbar or current clamp and lead to an oscillation that as previously stated can lead to damage. Back EMF can cause problems for regulated supplies as well. The current regeneration may be too large for the regulated supply to absorb and may lead to an over voltage condition.

Switching supplies are typically regulated and require little real-estate, which makes them attractive. However, their output response time is slow, making them ineffective for inductive loads. IMS has designed a series of low cost miniature non-regulated switchers that can handle the extreme varying load conditions which makes them ideal for the MDrivePlus.

Part 2: Interfacing and Configuring

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Intelligent Motion Systems MDrive34Plus manual Interfacing DC Power, Choosing a Power Supply for Your MDrive

MDrive34Plus specifications

The Intelligent Motion Systems MDrive34Plus is an advanced integrated stepper motor and drive solution designed for a wide range of industrial automation applications. This compact device combines the motor, drive, and control into a single unit, simplifying installation and minimizing space requirements. This makes it an ideal choice for applications where space and efficiency are critical.

One of the standout features of the MDrive34Plus is its high torque output, which enables it to handle significant loads with ease. Rated for a variety of torque configurations, this stepper motor provides the necessary power for demanding tasks while maintaining precise control and smooth operation. The MDrive34Plus also features a high-resolution microstepping capability, which enhances performance by providing smoother motion and reducing audible noise.

The device employs advanced digital control technologies, ensuring accurate positioning and minimizing erratic performance. Integrated with onboard intelligence, the MDrive34Plus allows for programmable settings, including acceleration, deceleration, and speed control, which can be customized according to the specific requirements of the application.

In terms of connectivity, the MDrive34Plus offers a range of communication protocols including RS-232, RS-485, and USB options, allowing it to easily integrate with various control systems and enable real-time monitoring and diagnostics. This flexibility is vital for modern automation solutions where adaptability is key.

The MDrive34Plus is also designed for robust performance in challenging environments, featuring an IP65 rated enclosure that protects against dust and moisture. This makes it suitable for use in a variety of industrial settings such as packaging, assembly, and robotics.

Furthermore, the MDrive34Plus supports both open-loop and closed-loop control configurations. This versatility provides users with the ability to choose the best operational mode for their application, optimizing performance and efficiency.

In conclusion, the Intelligent Motion Systems MDrive34Plus is a powerful, flexible, and easy-to-install integrated motor and drive solution. With its high torque capabilities, advanced digital control features, diverse connectivity options, and robust design, it stands out as an excellent choice for modern automation challenges. Whether for precise positioning tasks or heavy load handling, the MDrive34Plus is equipped to meet a broad spectrum of operational demands.