Elif Özaksu
Corporate
- Thread Author
- #1
In the world of industrial automation, data transmission latency still poses a significant problem. Simply defined, latency is the time it takes for data to travel from one point to another. However, this simple definition does not fully reflect its complex effects on automation technologies. In industrial applications where long latencies often lead to negative consequences, maintaining the lowest possible latency is vital. Zero latency may be a dream, but near-zero values are now achievable.
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🤖 Latency Thresholds and Impacts in Robotic Assembly Lines 📊
For robots to perform precise manufacturing tasks (assembly, welding, material handling, safety, etc.), they must synchronize reliably with each other. To achieve this precise synchronization, industrial robots need real-time decision-making capabilities, and minimizing latency is a critical factor at this point.
The first step in addressing this problem is to determine the maximum latency threshold an application can tolerate before production issues arise, and the minimum possible threshold. This requires real-time measurement and monitoring of latency.
Weidmüller's AdvancedLine series of managed switches enhance network availability by using network diagnostics, as well as redundancy and control mechanisms in automation networks.
In manufacturing environments, latency requirements vary by application. Basma Ahmed, Product Manager for Industrial Ethernet at Weidmüller, states that latencies of 1 to 5 milliseconds are generally acceptable in information technology (IT) systems, but many operational technology (OT) processes require extremely fast and consistent communication. In OT systems, even a 1-millisecond delay can lead to serious production consequences.
Ahmed adds that jitter, which are variations in latency, can be more disruptive than latency itself. This is because inconsistent timing creates unpredictability that systems cannot compensate for.
Daniel Mai, Director of Industrial Wireless Communication at Siemens, agrees with Ahmed, stating that meeting low latency levels alone is not sufficient in many industrial automation applications. According to Mai, the most important thing is predictable, deterministic communication. Since automation applications, synchronized processes, and safety-related coordination rely on consistent timing, deterministic behavior and low jitter (variation in latency) are elements that should be considered from the outset.
Traffic profiles are a suitable alternative to network slicing for providing Quality of Service (QoS) by handling critical control-related communication with different performance and security parameters and non-critical data flows within the same network.
Ahmed explains that real-time monitoring of latency and jitter can be done through packet time stamping, where industrial switches or edge devices add precise timestamps to packets at ingress and egress points. These timestamps measure end-to-end latency and jitter and determine where delays originate.
Managed switches also provide diagnostics, traffic monitoring, and network management capabilities.
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💡 Edge Computing and Distributed Processing 🏭
Edge computing plays a significant role in robotic deployment by keeping real-time data processing and decision-making close to manufacturing machines. The advantages of this form of distributed processing include reduced latency, better control, higher efficiency, and faster response to sensor data.
Additionally, distributed processing allows for the addition of numerous devices without straining the network.
Mai states that edge computing reduces latency by processing data close to machines and processes, rather than relying on remote cloud round trips. Edge nodes placed close to the production line or cell and OT network aggregation points keep network paths short and enable fast monitoring and analysis, as well as AI-based application responses.
The Siemens Scalance integrated industrial communication solutions portfolio includes managed and unmanaged switches, wired and wireless routers, protection for industrial networks and automation systems, and industrial wireless LANs.
In efforts to minimize latency in time-critical processes, Ahmed has observed that manufacturers often position edge computing nodes close to production equipment and connect them to industrial Ethernet switches. This is where security becomes an issue, especially when factory networks are connected to external systems, remote access platforms, or the cloud.
To address this, OT traffic should be isolated from less critical networks to enhance security and maintain deterministic performance.
Industrial companies should be aware that common security mechanisms such as firewalls and deep packet inspection can introduce additional latency and jitter when placed directly in time-critical communication paths. To avoid this problem, manufacturers should position security controls at network boundaries, not within real-time control segments.
By combining edge computing with a well-designed, segmented industrial network infrastructure and appropriately placed security controls, manufacturers can achieve both low-latency decision-making and secure, reliable connectivity in production environments.
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⚡ Balancing Latency and Reliability 🛠️
In addition to all the latency factors manufacturers need to consider, they also need to consider the potential impact on reliability. Here, it is important for manufacturers to evaluate the fault tolerance mechanisms (failover mechanisms) available to them.
"In industrial applications, availability and performance must be designable together," says Mai. "High reliability is not achieved by a single feature, but by an end-to-end design approach to implement redundancy where necessary, avoid single points of failure, clearly prioritize and separate traffic flows, and provide robust monitoring and diagnostics."
Since private 5G network connections occur via a gateway to the wired factory network or a router connected to an industrial Ethernet switch that connects controllers, PLCs, and SCADA systems, manufacturers should aim to minimize protocol conversions, maintain precise network timing via PTP (Precision Time Protocol), and use industrial-grade hardware.
In facilities with private industrial 5G setups, this often means operating a controllable radio environment with appropriate QoS (quality of service) concepts for different traffic classes, securing transitions to OT networks, and using architectures that keep critical functions local. This helps ensure stable latency and robust operation even under disruptions or heavy loads, without unnecessarily complicating the overall network.
"Manufacturers must balance high reliability with low latency when designing industrial networks," says Ahmed. "To maintain communication without creating significant delays during failures, they typically implement redundant network topologies, such as ring architectures or high-availability redundancy mechanisms supported by industrial Ethernet switches."
However, it is important to note that while redundancy helps reduce downtime, it does not eliminate latency and may not fully meet the needs of millisecond-level, time-critical systems, where even short transition times can have an impact. To maintain deterministic performance, manufacturers often rely on Layer 2/Layer 3 managed switches that provide fast transmission, traffic prioritization, and PTP (Precision Time Protocol)/IEEE 1588 support for accurate synchronization with time-sensitive networking. These technologies ensure predictable communication and minimal jitter across the network.
