Totzeit
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Dead time refers to the time span between a triggering event and the first measurable response of a system. In intralogistics, it affects control accuracy, buffer planning, and the reliability of SLA measurements.
Key facts
- should be questioned critically – even real-time systems have measurable dead times, which may or may not be relevant depending on the use case. When designing control loops in conveyor technology, it is recommended to measure dead times instrumentally and incorporate them into parameterization.</p>
- key_facts
What is dead time?
Dead time is the delay between the occurrence of an event and the point at which a system responds to it or the effect becomes visible. It is not downtime in the conventional sense, but rather an inherent system latency that occurs in technical control loops as well as in organizational processes. The key point is: during dead time, no information is available on which to base action – the system is, in a sense, blind to what is happening.
Dead time in intralogistics – how it arises
In warehouse and conveyor systems, dead time occurs at multiple levels. Technical causes include:
- Latencies between a sensor event and the processing response in the Warehouse Control System (WCS) or WMS
- Batch processing, where postings are not transferred in real time but at defined time intervals
- Network delays at wireless terminals, RFID read points, or cloud-based services
Process-related dead times arise wherever manual steps without immediate system feedback are involved – for example, when a goods receipt posting is only made after a pallet has been physically stored, even though the scan took place earlier. The warehouse is then physically occupied but not yet recorded in the system.
Impact on control and planning
Dead time is critical for all systems that must respond to current states. In automated facilities – such as conveyor lines, sorters, or automated guided vehicle systems – an unknown or underestimated dead time can lead to control errors, because corrective commands are triggered too late. In warehouse planning, it causes inventory information in the WMS to be time-lagged, meaning planners make decisions based on outdated data.
For SLA measurement, precise knowledge of dead times is essential: if a constant delay exists between a physical event and the system posting, it must be factored out when calculating throughput times or delivery reliability – otherwise, systematically distorted metrics will result.
What to look for when selecting a system
When comparing WMS, WCS, or automation components, it is advisable to explicitly request dead time specifications and measure them in test scenarios. Vendors provide varying information on this, and actual latency depends heavily on system architecture, network infrastructure, and configuration. Blanket promises such as "real time",