• • • COVER STORY • • •
Puls says the demand for flexible, modular systems is shaping the world of automation, control and machine building
Power decentralisation made easy D
ecentralisation of system components has proven to be an important factor in this growing trend. It speeds up the system
planning process, simplifies installation and maintenance, and facilitates future expansion. For many system builders and installers, the power supply has been an obstacle on the path to consistent decentralisation. In particular, where functions such as selective current distribution, protection and condition monitoring need to be implemented whilst providing maximum reliability and uptime.
Challenges and solutions For achieving a decentralised power supply, an obvious solution is to design a system that can be mounted directly on a machine or installation. The power supply and other standard components such as electronic fuses, communication terminals, distributor blocks or switches are relocated from the central control cabinet to smaller enclosures directly in the field. The installation of these components outside of a fully environmentally-protected central cabinet means they will require a high IP rating individually to ensure protection against dust and moisture. Providing protection to class IP54, IP65 or IP67 may be required, depending on the application. The result will be a small, decentralised on-site
cabinet for which the individual components have to be selected, ordered, stored, assembled and installed, a time-consuming and complex task. In most cases there is very little space available on a machine to locate a control system, so finding a
location for this cabinet can be problematic. Engineers often need to be creative, positioning the cabinets above or below the system making access sometimes difficult for installation and service technicians. However, compact all-in-one solutions for
decentralised applications are available, such as those form Puls. Its FIEPOS Field power supply family is based on a modular platform developed specifically for use outside of a cabinet. All models are based on either 1-phase or 3-phase input power with either a 300W or 500W output rating. All devices in the FIEPOS family provide 120% power continuously (up to +45°C) and 200% for 5s making them suitable loads with a demanding start-up cycle. With a housing size of only 182 x 183 x 57mm
(WxHxD), they can be installed even in applications where space is at a premium. The units can be mounted via DIN-rail or in place using a variety of mounting holes. The FIEPOS product family (Figure 2) has two
versions: The Basic series with one DC output which offers an optional integrated decoupling MOSFET for developing redundant power supply systems and the eFused series with up to four current-limited DC outputs. FEIPOS simplify the delivery of selective current distribution, protection and monitoring directly in the field, with no need for any further accessories, or costly, bulky enclosures. FIEPOS supplies are manufactured using a combination of modular boards futureproofing them by allowing new functions to be added by simply integrating alternative boards as required.
Selective current distribution
and protection The eFused range of FIEPOS power supplies offer an alternative to power sources that are protected either by means of an external electronic four- channel protection module, four external fuses or circuit breakers. To deliver selective current distribution, the eFused versions can integrate up to four electronic fuses allowing them to simultaneously supply electromechanical loads (e.g., motors) and sensitive loads such as controls or sensors from a single decentralised and fused power supply. If there’s a short-circuit, the power supply
selectively shuts down only the faulty output and reports this via the IO-Link or Output-OK signal and the LED interface on the front of the device. Due to active current limitation, all other outputs continue to be supplied with the proper voltage. This is particularly important in the case of sensitive and safety-critical loads such as PLCs or sensors.
Protected load branches Requirements can vary greatly from one application to another. For this reason, Puls has developed various circuit designs for the most common applications, and there are several possible configurations:
1. Two outputs – four load branches This configuration allows up to four separate load branches with two outputs each. For this requirement Puls offers three eFused models with an output power of either 300W or 500W. With these models, two separate electric circuits per output can be achieved, allowing sensors and actuators to be independent of each other. If one sensor load branch fails due to a fault, the other three continue to be supplied with power; see Figure 4. The fault is indicated via IO-Link and the status LED on the front of the device. The communications and LED status allows maintenance to be performed quickly and efficiently. The tripped channel is reset using the pushbutton on the front of the device or alternatively, via IO-Link.
2. Three outputs – three load branches These options provide up to three separate and individually-protected load branches with one power supply for several sensors and actuators with power via each load branch; see Figure 5. If a sensor connected to output 1 fails, the
electric circuit is open. All sensors and actuators connected to the faulty output are no longer supplied with power. The fault is indicated via IO- Link and the status LED on the front of the device. Outputs 2 and 3 remain unaffected by this fault, and the power to these outputs is maintained.
10 ELECTRICAL ENGINEERING • JULY/AUGUST 2022
electricalengineeringmagazine.co.uk
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