SIMATIC S7-1500 R/H for redundancy and high availability
Avoid plant downtime with redundant automation solutions
Maximum plant availability is essential – but how can you achieve this goal? The redundant and high-availability SIMATIC S7-1500 R/H CPU is the answer. A backup CPU synchronized with the primary CPU ensures that no data is lost in the switchover. And best of all, synchronization and project consistency are a system function. Which means that you don’t need special knowledge to use a SIMATIC S7-1500 R/H CPU: The engineering is performed in TIA Portal as usual.
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Redundant systems reduce costs and increase productivity
Machine and plant downtime nearly always means production outages. In the worst case, an unplanned plant outage can damage the product or the machinery, which incurs more costs. Redundant systems can prevent outages in many cases, they’re easier to maintain than application-based solutions, and they may also meet legal requirements. But if a CPU outage occurs, production can continue because the backup CPU takes over seamlessly. And because service technicians aren’t always on-site, you have more time to schedule service work.
Safety, security, availability – the key elements
In addition to availability, safety and security are two more key factors in plant operation, although they differ greatly in terms of their focus and effects. Safety protects people and machines if a fault occurs, and it puts the plant units in question in a safe state: I other words, it brings them to a stop in most cases. Security prevents attacks from outside like cyber attacks or sabotage and so helps maintain availability. Redundant solutions enable what’s known as “hot standby” to ensure that the plant can continue to run in the event of an outage or other unforeseen events. This involves linking redundant CPU pairs together via PROFINET. High-availability CPU pairs are connected using synchronization modules and fiber-optic cable, which shortens the switchover time for H-CPUs by about a factor of six to 50 ms. The IO periphery is connected to the primary and backup CPU as a switched S1 or S2 device via the PROFINET ring and the media redundancy protocol (MRP).
Hot standby: To ensure that nothing happens when a CPU fails
Redundant CPUs are synchronized via PROFINET and are suitable for less time-critical applications where CPU availability combined with spatial proximity is very important. High-availability CPUs support applications where a short switchover time and a greater distance are also important, in addition to availability. This is where dedicated synchronization modules and fiber-optic cables come in. The primary CPU is programmed just like a standard CPU: The backup CPU is automatically fed the same program by the system and synchronously monitors the primary CPU in operation.
Avoid financial losses
Outages in baggage handling systems at airports are usually annoying, but they’re also costly if they result in delays in flight schedules. In warehouses and other logistics areas, outages can cause the supply chain to break down, which will quickly lead to significant financial losses because the next processes in the sequence will also be brought to a stop. The consequential costs will usually exceed the cost of investing in redundant systems many times over. This is where a decentralized IO system structure is recommended, with an active backplane bus in addition to a SIMATIC S7-1500 R/H CPU for maximum availability.
Reliable operation must always be assured
For safety reasons, systems in tunnels such as traffic control, ventilation, smoke extraction, and lighting must always be fail-safe. High-availability SIMATIC S7-1500 H CPUs can be synchronized over up to about 6.2 miles. This is a huge advantage in tunnels, which can often reach lengths of several kilometers, and it also makes it easier to construct redundant systems. If the safety requirements increase – for legal reasons, for example – the CPUs can be expanded by adding new fail-safe software blocks to provide optimal investment protection.
When constant air-conditioning is essential
In many areas it’s essential to have an air-conditioned atmosphere, even outside regular work hours. Outages that affect equipment for ventilation or air treatment – including humidification and heating – must therefore be reliably prevented. But if a fault occurs, it’s vital to rectify it as soon as possible. This is where it’s practical to have a redundant solution that uses SIMATIC S7-1500 R CPU in place.
Decentralized structure for decentralized devices
Pumps for water treatment are often distributed across multiple sedimentation tanks – along with the IOs. Because the treatment process is relatively slow, it’s not essential for the CPUs to be high-availability. A decentralized structure for the IO system ensures that a short-term outage affecting a single station will remains non-critical and the system can continue operating. If a higher level of availability is also required at the CPU end, SIMATIC S7-1500 R CPUs will do the job – depending on the quantity framework, SIMATIC S7-1500 H CPUs are also used.
Central CPU structure
Minimal space requirements and high cost pressures are important factors in mechanical engineering. Machines are normally switched off at the end of a shift and aren’t left to run unsupervised. That’s why these cases usually involve a central structure with just a single CPU. If individual sensors or IO channels fail, it’s easy to bypass them thanks to their deliberately redundant configuration.
