VariableReadActivity

Category: Common Steps Namespace: CMS.Plugin.FlowManagement.Domain.FlowBusiness.Activitys Base Class: BusinessActivity Module: FlowManagement.Domain

Overview

VariableReadActivity (Read Variable) is a node used to read external variables (such as PLC variables) in the process. It inherits from BusinessActivity and reads variable values via the IFlowVariableService service, writing them to the process context.

Configuration Description

Property Name	Type	Required	Default	Description
CheckVariableName	bool	No	false	Whether to check variable configuration
ReadRetryCount	int	No	3	Read retry count
ReadRetryDelay	int	No	500	Read retry delay (milliseconds)
ParameterVariables	ReadParameterVariables	No	Empty Collection	Parameter variable collection

Parameter Variable Configuration

Property Name	Type	Description
VariableName	string	Variable Name
FlowItemKey	string	Process Context Key Name
WriteIntoDataItems	bool	Whether to write to process context

Usage Examples

{
  "Type": "VariableReadActivity",
  "Name": "Read PLC Variables",
  "Alias": "ReadPLCVars",
  "ReadRetryCount": 3,
  "ReadRetryDelay": 500,
  "ParameterVariables": [
    {
      "VariableName": "DB1.Temperature",
      "FlowItemKey": "Temperature_Value",
      "WriteIntoDataItems": true
    },
    {
      "VariableName": "DB1.Pressure",
      "FlowItemKey": "Pressure_Value",
      "WriteIntoDataItems": true
    }
  ]
}

Notes

• 💡 Supports batch reading of multiple variables.
• 💡 Automatically retries on read failure.
• ⚠️ Requires variable service (IFlowVariableService) configuration.

Related Nodes

• VariableWriteActivity: Write Variable Node
• VariableMonitorActivity: Variable Monitor Node

Update History

Date	Version	Description
2025-11-28	1.0	Initial version

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Last updated: 2025-11-28