24 V nonstop - even upon power failure - 7 Pages

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24 V nonstop - even upon power failure

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24 V nonstop – even upon power failure The right UPS system for every application – summary of advantages and disadvantages A reliable power supply is essential for guaranteeing the productivity of automated plants and machines. PLCs, sensors and actuators are usually provided with 24 V DC from a switched-mode power supply. Modern power supply units such as SITOP offer a maximum degree of security for the supply. However, they are not invulnerable to longer power supply failures. uninterruptible power supply. But which UPS system is the right one, and what must be considered when dimensioning? AC or DC UPS? In order to provide protection against power failure, an uninterruptible power supply can be used on the AC or DC side. The advantage of an AC UPS is that it provides buffering of all electrical consumers, e.g. also of AC drives. However, an AC UPS is more expensive than a DC UPS. If it is permissible with the application to only buffer the 24 V side in the event of a power failure, a DC UPS is quite definitely the more economical solution. On the one hand, the powers required are usually smaller, resulting in smaller dimensioning of the DC UPS, and on the other hand an AC UPS is always more expensive because of its increasingly complex design. Furthermore, the total efficiency is significantly better with a DC UPS. This is because conversion of the battery voltage into an AC voltage and the repeated transformation into the required 24 V DC voltage are unnecessary. With the DC UPS, the energy is provided where it is required, namely directly on the consumer without "loss-making detours". Figure 1: With this control cabinet for controlling a crane system, an AC UPS which had to be mounted on top of the cabinet because of its size (photo left) was replaced by three DC UPS modules. Since the more compact SITOP PSU300M 24 V/ 20 A generation of power supplies was used at the same time, all three power supplies even fitted together with the three SITOP UPS500S 15A/5 kW modules on the same DIN rail. Power Supply SITO

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The right solution for every application No other manufacturer of power supplies provides such a comprehensive range of units for safeguarding a 24 V DC supply like Siemens does. The range extends from a simple buffer module up to the multi-function DC UPS. Three different solutions can be used depending on the Buffer module Add-on module with electrolytic capacitors for bridging brief power (allures. Can be combined with SITOP smart and modular. Low-cost protection against power failures for seconds Completely maintenance-free Support of the power supply un when the demand fbr current is...

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Available capacity of lead batteries is highly dependent Lead batteries are extremely temperature-sensitive, since the charging and discharging processes of a battery are the result of an electrochemical reaction. Aging depends on the electrolyte used (sulfuric acid) and the plates serving as poles (lead and lead oxide), and is highly temperature- dependent. Temperatures higher by 10 K reduce the service life by half. With an ambient temperature of 40 °C, for example, the service life is therefore only 114 of that at the rated operating temperature of 20 °C. A lead battery with a service...

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Application conditions: Time required to save and shut down the system: 55 s, 1) Calculation of current requirements and selection of power supply a) Calculation of max. operating current requirement: Buffered 24 V feeder: 2.7 A (PC 477D) + 1 A (sensors) + 2 Non-buffered 24 V feeder: 3 A (actuators) Total operating current requirement: 5.7 A + 3 A = 8.7 A b) Calculation of peak current requirement: (sensors) + 2 A (charging current) = 10.5 A Non-buffered 24 V feeder: Actuators: 4 A (starting Total peak current requirement: 10.5A + 4A = 14.5A c) Selection of power supply for 8.7 A operating...

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How is the DC UPS integrated into the plant? The automation system must be informed about the status of the DC UPS so that it can respond correctly to the situation. Communication takes place via digital outputs, USB or Ethernet/PROFINET interfaces. Table 3: A free engineering tool is available for the DC UPS with interface and controller type that must be buffered; it can be used for easy configuration of the DC UPS and visualization of Digital outputs The most important status messages are displayed by LEDs for all SITOP DC UPS modules and output via signaling contacts. The signals are...

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The events to which the UPS1600 can respond are identical for USB port and Industrial Ethernet interface. When compared to signaling via contacts, you can also evaluate the remaining buffer time and the status of the battery charge via these ports. This means a more timely response to critical states is possible. Parameters can be conveniently assigned via the SITOP UPS Manager. It offers additional visualization compared to the DC UPS Tool (for UPS500 and the predecessor DC UPS 6EP1931…): • • • Figure 5: Backing up a 24 V automation computer with communication via USB Monitoring of pending...

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In addition, all device parameters can be read, for example, end-of-charge voltage, rated capacity, permissible temperature range, article number, serial number and version number. SITOP UPS with PROFINET on process control systems A free UPS1600 library with software blocks and faceplates is also available for the SIMATIC PCS 7 process control system. Automatic information about operating status messages such as power failure (buffer mode) or maintenance demanded as well as preventive battery replacement increase availability of the plant in process automation even more. Figure 8: Backing...

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