MOTOR Logic Block Documentation

Overview

The MOTOR function block is used to control electric motors within an automation or process control system. It is designed to manage both manual and automatic operations, monitor motor health, and ensure safety through permissive and interlock logic.

This block is crucial for applications requiring reliable motor operation, feedback verification, start/stop control, and operational diagnostics.

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Logic Block Description

The MOTOR block facilitates the following operations:

• Start/Stop Motor: Based on HMI/Auto commands and remote-local (RL) selection.
• Monitor Feedbacks: Ensures the motor is running or tripped using feedback inputs.
• Safety Checks: Includes internal and external interlock and permissive logic.
• Diagnostics: Provides outputs for failed feedback detection, local control detection, and fault alerts.
• Runtime Tracking: Tracks motor run time, number of starts, and delay management.

Showing the MOTOR block in the above picture.

The above picture shows how the inputs and outputs are connected in the MOTOR block.

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Input and Output Parameters

Signal	Type	Description
ioRunFB	BIT	Motor run feedback signal
ioTripFB	BIT	Motor trip feedback signal
ioRL_Selection	BIT	Remote/Local selection signal
ioCommand	BIT	Motor output command
Command	BIT	Motor output command from logic
perm	BIT	Internal permissive condition
intl	BIT	Internal interlock condition
RFB_Fail	BIT	Run feedback failed (e.g., motor did not start after command)
Diagnostics	BIT	General diagnostic output (e.g., motor faulted or issue detected)
LocalStarted	BIT	Motor started locally
LocalStopped	BIT	Motor stopped locally
hmiStartCMD	BIT	HMI start command
hmiStopCMD	BIT	HMI stop command
ExtIntl	BIT	External interlock condition
ExtPerm	BIT	External permissive condition
AM_Sel	BIT	Auto/Manual selection
AutoStart	BIT	Auto mode start command
AutoStop	BIT	Auto mode stop command
fp_Visible	BIT	Visibility of the faceplate on HMI
RFB_CheckTime	WORD	Time allowed for run feedback to respond
HMI_Interface	WORD	Interface code/messages for HMI display
byPerm_Intl	BYTE	Combined status byte for interlock and permissive
StartCount	INT	Number of motor starts
RunTime	REAL	Total run time of the motor (in hours)
MTM	REAL	Maximum allowed time for run feedback to appear
RFB_FailTime	REAL	Time when run feedback failed
CycleTime	REAL	Time for one control cycle
IntlBypass	BIT	Bypass for interlock (manual override)
PermBypass	BIT	Bypass for permissive (manual override)
TagName	STRING(10)	Tag name for the motor (used in faceplate and diagnostics)
Desc	STRING(12)	Description of the motor

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Operational Behavior

Start/Stop Sequence:

• If in Auto mode (AM_Sel), motor will start/stop based on AutoStart/AutoStop.
• If in Local mode and RL_Selection = FALSE, motor will start on hmiStartCMD.

Safety Conditions:

• The motor will only start if all permissive and interlock conditions are valid, or bypass is enabled.

Feedback Monitoring:

• After issuing a start command, the block waits for a valid ioRunFB within RFB_CheckTime.
• If not received, RFB_Fail is set.

Diagnostics and Messaging:

• Faults, feedback issues, and local operation are logged through Diagnostics and HMI_Interface.

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Best Practices

• Ensure accurate RFB_CheckTime configuration to match motor start delay characteristics.
• Use IntlBypass and PermBypass only during maintenance or special cases.
• Monitor RunTime and StartCount for motor maintenance and analytics.
• Use descriptive TagName and Desc values for better HMI display and diagnostics.
• Properly map HMI_Interface to corresponding HMI messages for real-time troubleshooting.

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Summary

The MOTOR block provides a safe, intelligent, and flexible structure to control electric motors within automation systems. It enables both manual and automatic modes, incorporates fault detection and interlock logic, and ensures that motor operations comply with system safety and reliability requirements.

Designed to enhance motor protection, simplify control logic, and streamline HMI interactions.