Pump Alternation Logic FBD

Pump alternation logic FBD

This FBD separates pump selection into two readable networks. The first network drives pump 1 from a high-level demand and its availability signal. The second network provides a fallback for pump 2 by checking that pump 1 is not available. It is a useful starting point for a sump or lift-station control narrative, but a deployed program should also define motor protection, stop conditions, alarms, and the site-specific safety interlocks. Before using the layout in a build or document, compare every label with the source requirements and update the drawing when parts, conditions, or materials change. The example is deliberately small so the essential relationships remain readable, easy to review with collaborators, and ready to extend with the details required for the actual project.

類型 功能方塊圖標準 IEC 61131-3:2013 §6.4引擎 schematex-fbd更新時間 2026/9/24

需求

“Create an FBD that runs pump 1 when high level and pump 1 is available, and runs pump 2 when high level, pump 1 is unavailable, and pump 2 is available.”

接著試試Add a low-level stop input to both outputs.Add a run-hour alternation input.

這張圖裡有什麼

看懂背後的決策。

01Demand

High level starts the selection.

02Priority

Pump 1 is the preferred available pump.

03Fallback

Pump 2 runs only when pump 1 is unavailable.

Use as a simple selection pattern before adding interlocks, faults, and alternation memory.

瀏覽所有功能方塊圖範本 →

常見問題

What is an FBD network?

It is a grouped set of function blocks that performs one part of the control logic.

Why is pump 1 negated for pump 2?

The fallback runs only when the preferred pump is unavailable.

Does this alternate pumps?

No. It selects a preferred pump; alternation needs additional state logic.