Python Motor Control System — LabJack UE9

Python application controlling a DC motor via LabJack UE9 over Ethernet — forward/reverse direction, emergency stop, and reset-gated resume logic.

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Overview

This project implements a hardware motor control system in Python, communicating with a LabJack UE9 data acquisition device over Ethernet to drive an L293 H-bridge motor driver. The system supports forward and reverse motor control, an emergency stop with hardware button detection, and a safety gate that prevents the motor from resuming until the user explicitly confirms after a reset button press.

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Hardware

Component	Detail
Controller	LabJack UE9 (Ethernet)
Motor Driver	L293 H-Bridge
Interface	Ethernet TCP/IP
Input	Hardware reset button (FIO3)
Output	DC Motor (bidirectional)
Logic	Active-low via optocouplers

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Pin Mapping

FIO Pin	Signal	Function
FIO0	ENABLE (OP3)	Motor enable — HIGH = running
FIO1	DIR_A (OP1)	Direction control A
FIO2	DIR_B (OP2)	Direction control B
FIO3	RESET	Hardware reset button input

Motor direction truth table:

DIR_A	DIR_B	EN	Result
HIGH	LOW	HIGH	Forward
LOW	HIGH	HIGH	Reverse
X	X	LOW	Stop

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Features

• Forward / Reverse motor control via terminal commands
• Emergency stop — immediately disables motor enable pin
• Reset-gated resume — motor only restarts after hardware button press AND explicit user confirmation
• Debounced reset detection — 50ms hardware debounce on reset button
• Safe initialization — all pins set to safe state before operation begins
• Clean shutdown — motor stopped safely on quit

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Setup

Requirements

pip install LabJackPython

Configuration

Update the LabJack UE9 IP address in motor_control_system.py:

return ue9.UE9(ethernet=True, firstFound=False, ipAddress="YOUR_UE9_IP")

Run

python motor_control_system.py

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Commands

Key	Action
f	Run motor forward
r	Run motor reverse
s	Emergency stop (requires reset button + confirmation to resume)
q	Quit and stop motor safely

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System Flow

Start → safe_start() → wait for command
  f → motor_forward()
  r → motor_reverse()
  s → motor_stop() → wait_for_reset() → user confirm → resume / stay stopped
  q → motor_stop() → close connection → exit

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Author

Romil Chauhan — Computer Engineering Technology, Seneca Polytechnic 📧 chauhanromil1@gmail.com 🌐 romilchauhan.github.io 💼 linkedin.com/in/romilchauhan1111