June 18, 2018

Motor operation based on time cycle sequence

Motor Operation Based on Time Cycle Sequence

A Practical Guide for Automation Professionals and Students

In industrial automation, motors are the backbone of countless processes—from conveyor systems and pumps to mixers and compressors. While many motor operations are triggered by sensors or manual inputs, time-based motor sequencing offers a powerful method for controlling multiple motors in a predictable, repeatable pattern. This approach is especially useful in applications where operations must follow a strict timeline, regardless of external conditions.


This article explores the concept of motor operation based on time cycle sequences, its implementation using PLCs, and its relevance in modern automation systems. Whether you're a student learning the basics or a professional designing control panels, this guide will help you understand and apply time-based motor control effectively.

What Is Time Cycle-Based Motor Operation?

Time cycle-based motor operation refers to the activation and deactivation of motors according to predefined time intervals. Instead of relying on external triggers like sensors or switches, the system uses timers to control when each motor turns ON or OFF.

This method is particularly useful in:

  • Sequential operations (e.g., mixing, filling, packaging)

  • Load distribution across motors

  • Preventing simultaneous startup to avoid current surges

  • Repetitive tasks with fixed durations

Example Scenario: Three-Motor Sequence

Let’s consider a simple example involving three motors (M1, M2, M3). The goal is to operate them in a specific sequence over a 30-second cycle:

Time Interval (sec)Motor 1 (M1)Motor 2 (M2)Motor 3 (M3)
0–5ONOFFON
5–10ONOFFOFF
10–25OFFONOFF
25–30OFFOFFON

This sequence repeats continuously as long as the system is active.

PLC Implementation: Ladder Logic Approach

To implement this logic, we use a Programmable Logic Controller (PLC)—such as Siemens S7-1200 or S7-300—with ladder logic programming. The system includes:

  • START and STOP push buttons

  • Timers (TON or TP)

  • Motor output coils (Q0.0, Q0.1, Q0.2)

Visualization: Time Cycle Diagram

To help students and professionals visualize the sequence, a time cycle diagram is essential. It shows the ON/OFF status of each motor across the timeline, making it easier to understand and debug

Time (sec) → 0   5   10   25   30  
M1         → ────ON─────OFF────────  
M2         → ────────ON─────OFF────  
M3         → ON────OFF────────ON────

This diagram can be included in training kits, SCADA screens, or HMI interfaces to enhance clarity.

Real-World Applications

Time-based motor sequencing is widely used across industries. Here are a few examples

1. Conveyor Systems

In packaging plants, different conveyor belts may need to run in sequence to move products from one station to another. Time-based control ensures smooth transitions.

2. Pumping Stations

In water treatment facilities, pumps may operate in cycles to balance load and prevent wear. Time sequencing helps automate this process.

3. Mixing Operations

Chemical or food processing units often require ingredients to be added and mixed in a timed sequence. Motors controlling mixers and feeders follow a strict time cycle.

4. HVAC Systems

Fans and compressors in HVAC systems can be staged based on time to optimize energy usage and reduce peak loads.

Educational Value

For students and trainees, this topic offers a hands-on way to learn:

  • Timer functions in PLCs

  • Ladder logic programming

  • Sequential control design

  • Visualization and debugging techniques

It’s also a great opportunity to introduce real-time monitoring, HMI integration, and SCADA visualization, making the learning experience more industry-relevant.

Tips for Implementation

Here are some best practices when designing time cycle motor operations:

  • Use retentive timers if the cycle needs to resume after power loss

  • Label time ranges clearly in your code and diagrams

  • Include manual override options for safety and maintenance

  • Test with simulation tools before deploying on actual hardware

  • Document the logic for future troubleshooting and training Integration with SCADA and HMI

To make the system more interactive and user-friendly, integrate the motor sequence with SCADA or HMI platforms. This allows operators to:

  • View motor status in real time

  • Adjust time intervals dynamically

  • Start/stop the cycle from a touchscreen

  • Receive alerts if motors fail to operate as expected

Platforms like WinCC, FactoryTalk, or InduSoft can be used to build intuitive interfaces.






Selective execution of the application