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Level relay

Regular price €2,90 EUR
Regular price Sale price €2,90 EUR
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Description

The FB_LevelRelay function block monitors a level and evaluates whether it is within a predefined range. It realistically maps normally closed and normally open contacts (13–14 / 21–22), including optional input enable and simulation mode. The internal state #Level_OK signals a valid level; the outputs follow this state, taking the inputs into account.

Note: This logic is intended as a template. It must be integrated, tested, and approved by qualified personnel before productive use. Improper integration may result in incorrect level evaluation or unexpected switching behavior.

How it works
Reset

With #Reset , the block is reset to a safe initial state: Normally closed contact ( #NO_13_14 ) inactive, normally open contact ( #NC_21_22 ) active (error/idle state). Status shows Reset, errors are reset.

Disabled

If #Enable is not set, both contacts remain off. The block behaves passively without error indication.

Level rating

The current level ( #Level ) is checked: It is considered valid if it is between the lower and upper limits ( #LO_Limit ≤ #Level ≤ #HI_Limit ), then #Level_OK is set.

simulation

In simulation mode, the contacts are controlled directly via #Level_OK : Normally closed contact is activated when the level is valid, normally open contact when the level is invalid.

Normal operation

In real operation, the inputs also act as releases:

  • #NO_13_14 is only active if #Input_13 is set and the level is valid.
  • #NC_21_22 is only active if #Input_21 is set and the level is out of range.

Status and diagnostics are reset if no errors are present.

Technical details
  • Inputs: #Enable , #Reset , #SimMode , #Level , #LO_Limit , #HI_Limit , #Input_13 , #Input_21
  • Internal state: #Level_OK – TRUE if level is within the allowed range
  • Outputs: #NO_13_14 (normally closed), #NC_21_22 (normally closed)
  • Status & Diagnosis: #Error , #Status , #DiagnosticCode
  • Modes: Reset, Disabled, Simulation, Real-time
  • Logic: Area check with optional input release and realistic contact mapping
Possible applications
  • Level control with defined switching conditions
  • Pre-validation of level conditions in simulation mode
  • Integration into process and alarm chains for status feedback
  • Linking sensor values with approved contacts for safe processes

Note: A complete technical inspection and approval by qualified personnel is required before productive use.

compatibility
  • Can be used in PLC systems with SCL support (e.g. Siemens TIA Portal)
  • Modular integration into higher-level control, safety and diagnostic architectures
  • Simulation allows safe tests without real level changes
  • Safe basic state when deactivated
Scope of delivery

You will receive:

  • An SCL file with the implemented function block FB_LevelRelay
  • Complete declaration of all inputs/outputs and internal states
  • Commented logic for quick adaptation
  • Quick guide to integration into automation projects

The download link will be provided after purchase.

Support

I am happy to support you with:

  • Adjustment of level limits and release logic
  • Integration into control and alarm chains
  • Simulation and validation before live use
  • Specific extensions for your application

Contact is possible via shop message or email. Extensions are available as optional customizations.