Current Monitoring Modularized to the Maximum Effect

Power supply systems are the heart of machines and systems and provide the required energy. This is why they must not be shut down by overcurrents or short-circuits which result in machine downtime, production losses and high costs. Maximum reliability of the power supply systems is essential!

Mico Pro from Murrelektronik guarantees reliable power supply systems. This intelligent current monitoring system from Murrelektronik monitors all load and control currents in a consistent manner and identifies critical moments at the right time. Mico Pro signals limit loads and switches defective channels off in a targeted manner to prevent total system crashes, and to assure a high level of machine availability. The tripping process has been patented, and applies the principle of “as late as possible, as early as necessary.” But Mico Pro also identifies “volatile” errors, such as a cable break in drag chains that only occurs at certain movement angles. Mico Pro identifies capacitive loads and starts them up in a controlled way.

Modular design that saves space

Mico Pro is a modular system for 12 and 24V DC operating voltages. The components can be selected for the particular application from numerous Mico Pro modules and connected without tools via a power module to form a closed system. You can select between modules with one, two, or four output channels. Their narrow width of 8, 12, or 24 millimeters enables significant savings in space. For example, a system with eight channels requires up to 65 percent less space than a system with circuit breakers. The more channels you use, the higher the percentage will be.

On the Fix modules, the tripping currents (2, 4, 6, 8, 10, and 16 A) are fixed which makes them a tamper-proof solution. On the Flex modules, the tripping current can be adjusted at the touch of a button from 1 to 10 A or from 11 to 20 A. This increases flexibility (e.g. for machine and plant manufacturers with option management), while reducing the number of versions required. It is thus possible to configure a customized Mico Pro system for each application. The system assures flexibility at all times. If a single module needs to be replaced, for example due to the power requirement of a new machine component, this can be done without tools in a short time. This ensures an advantageous cost-benefit ratio.

Significant simplification in switch cabinet wiring

Mico Pro has an integrated potential distribution concept for +24 (or +12) and 0V that significantly simplifies switch cabinet wiring. There are connection options for +24V and 0V on each channel. External 0V terminals are now a thing of the past – the zero potential can now be connected directly by Mico Pro. This helps to declutter installations, significantly reduce the amount of wiring needed and save not only space in the switch cabinet but also costs. Additional potential distributors enable connection of up to 2 x 12 potentials to each Mico channel.

Convenient handling

The innovative bridging system, which is used to connect individual components to a closed system is easy to handle. To mount the system designed for a total current of up to 40A, you just have to trim two bars to the right length with standard side-cutting pliers and insert them in the provided fixtures from the front in one quick step. Signal contacting for diagnostic and control signals takes place via laterally integrated spring contacts. The individual cables can be wired without tools since all inputs and outputs of the system are provided with push-in spring clamp terminals. Thus, mounting can be done in very short time and no maintenance is required during operation. The front side of the Mico Pro is at no time hidden by cables or lines; the operator has a clear view of all markings, labels and the status of the LEDs.

Diagnostics – on the module or via the controller

Great importance is attached to the diagnostic functions of Mico Pro. Each channel is equipped with an LED for status indication on the device and digital status signals can be transferred to the controller. The Mico Pro power module provides group diagnostics for the entire system and the adjustable Flex modules offer channel-specific diagnostic signals.

The status LED lights green as long as everything proceeds normally. Once a share of 90 percent of the preset or predefined tripping current has been reached, the LED flashes green to signal that the limit range (’90 percent early warning‘) has been reached. This may occur if additional consumers are connected, or the power consumption of already connected consumers increases, e.g. due to wear. When installing, the early warning may help to immediately identify incorrectly dimensioned current paths. Mico Pro triggers an additional digital status signal in such a case.

If the tripping current is exceeded, Mico Pro immediately switches the concerned channel off in a targeted manner. The LED flashes red and in this case, too, a status signal is sent. The operator may reactivate the channel by pressing a button on the module or via a PLC signal. For maintenance purposes, channels may also be switched off manually. Then the LED is lit red permanently and remote switch-on option is deactivated.

Mico Pro replaces the coupling plane

A channel-specific switching function via a PLC signal allows the Flex modules to switch system components on and off without any additional contactors, relays, or optocouplers. This solution can be used to replace the coupling level. Not only short switching frequencies (of up to 10 Hz) but also longer frequencies can be realized, for example to switch certain machine areas to the standby mode during non-production times. In this case, the LED of the affected channel lights orange.

Mico Pro can be cascaded. This means: on a Mico channel with a tripping current of more than 10 A, another Mico Pro station can be connected. If its channels are all provided with a tripping current of up to 10 A, full selectivity is guaranteed and the channels affected by short-circuits or overloads are still triggered accurately. The savings in money and installation work are considerable, especially in the case of applications with a decentralized switch cabinet concept as they do not require an additional power supply device.

Practical features in the details

• Mico Pro monitors channel currents of up to 20 A in a modular system – an innovation in modular current monitoring systems
• Optimum label options to keep the switch cabinet layout clear and simple
• Measuring possibilty for measuring diagnostic and status signals as well as outputs
• Non-volatile error memory: ideal for troubleshooting after a voltage reset
• High inrush capacities of up to 30 mF per channel, also at full load
• Operation now also possible with 5 A power supply units
• Minimum internal resistance, almost no power loss
• No temperature dependence
• Time delayed start of individual channels on multiple-channel modules to prevent current peaks.