A Guide to FANUC Servo Amplifier Alarm Codes


FANUC Servo Amplifier

Understanding FANUC servo amplifier alarm codes is crucial for maintaining peak performance in CNC (Computer Numerical Control) machines. These alarm codes serve as warning signals, indicating potential issues within the servo amplifier system. Ignoring or misinterpreting these alarms can lead to costly downtime, decreased productivity, and even damage to the machinery.

By comprehensively understanding these alarm codes and their associated troubleshooting measures, machine operators and maintenance personnel can swiftly address issues. This minimizes disruptions to production schedules and ensuring the longevity of the equipment.

Read more: A Guide to FANUC Servo Amplifier Alarm Codes

Understanding FANUC Servo Amplifiers

FANUC servo amplifiers are integral components of CNC (Computer Numerical Control) machines. These amplifiers are responsible for controlling the movement of servo motors, which are pivotal in driving the various axes of motion within the CNC system.

Servo amplifiers receive signals from the CNC controller and translate them into precise voltage and current outputs to drive the servo motors accurately. This precise control is essential for achieving the exact positioning, speed, and torque required for machining operations.

The significance of FANUC servo amplifiers lies in their ability to translate digital commands into precise mechanical motion, ensuring the repeatability and accuracy demanded by modern manufacturing processes. Servo amplifiers play a critical role in achieving optimal performance in CNC operations. That includes producing complex parts with tight tolerances or executing high-speed machining tasks.

Understanding the function and operation of FANUC servo amplifiers is fundamental for CNC machine operators and maintenance personnel. It allows them to troubleshoot issues effectively, optimize performance, and maintain the reliability and precision of the machinery throughout its operational life.

Troubleshooting FANUC Servo Amplifier Alarms

When troubleshooting FANUC servo amplifier alarms, it’s essential to follow a systematic safety procedures to identify and resolve issues effectively. Here are some basic tips to consider:

Prepping to Troubleshoot

  1. Safety First: Before starting any troubleshooting procedures, ensure the CNC machine remains powered off and safely isolated from the power source. Furthermore, follow all recommended safety procedures. This includes using appropriate personal protective equipment (PPE) when working with electrical components.
  2. Refer to Documentation: Consult the FANUC servo amplifier manual or documentation provided by the manufacturer for specific alarm code definitions, troubleshooting steps, and safety precautions. Familiarize yourself with the layout and components of the servo amplifier system.

Checking Equipment

  1. Check Connections: Inspect all electrical connections, including power cables, signal cables, and feedback cables, for any signs of damage, looseness, or corrosion. Ensure that connections are secure and properly seated.
  2. Review Alarm Codes: Take note of the specific alarm code displayed on the CNC machine’s control panel or diagnostic interface. Cross-reference the code with the manufacturer’s documentation to determine the potential cause of the alarm.
  3. Inspect Servo Motors: Check the servo motors for any mechanical issues such as binding, excessive wear, or damage to the shafts, couplings, or encoders. Next, check the motors for proper lubrication and potential debris.
  4. Test Power Supply: Verify that the power supply to the servo amplifier remains stable and within the specified voltage range. Use a multimeter or other appropriate testing equipment to measure voltage levels and identify any fluctuations or abnormalities.
  5. Reset Alarms: In some cases, resetting the alarm may temporarily clear the fault condition and allow the machine to resume normal operation. Make sure to do this after identifying and addressing the underlying cause of the alarm.


  1. Document Findings: Keep detailed records of the troubleshooting process, including observations, measurements, and actions taken. This information may prove valuable for future reference and for communicating with professional technicians if needed.
  2. Know When to Seek Help: If you encounter alarm codes or issues that you are unable to resolve , it’s important to seek assistance from qualified professionals or FANUC-certified technicians. Moreover, attempting complex repairs without the necessary expertise can lead to further damage or safety hazards.

Encountering an Issue with Your FANUC Servo Amplifier?

Get expert assistance now, to minimize downtime and keep your operations running smoothly. MRO offers a wide range of repair services and replacement parts.

Common FANUC Servo Amplifier Alarm Codes

0 PLEASE TURN OFF POWERA parameter which requires the power off was input, turn off power.
1 TH PARITY ALARMH alarm (A character with incorrect parity was input). Correct the tape.
2 TV PARITY ALARMTV alarm (The number of characters in a block is odd). This alarm will be generated only when the TV check is effective.
3 TOO MANY DIGITSData exceeding the maximum allowable number of digits was input. (Refer to the item of max. programmable dimensions.)
A numeral or the sign “ – ” was input without an address at the beginning of a block. Modify the program.
5 NO DATA AFTER ADDRESSThe address was not followed by the appropriate data but was followed by another address or EOB code. Modify the program.
6 ILLEGAL USE OF NEGATIVE SIGNSign “ – ” input error (Sign “ – ” was input after an address with which it cannot be used. Or two or more “ – ” signs were input.) Modify the program.
7 ILLEGAL USE OF DECIMAL POINTDecimal point “.” input error (A decimal point was input after an address with which it can not be used. Or two decimal points were input.) Modify the program.
Unusable character was input in significant area. Modify the program.

Raspberry Pi in Industrial Automation

For quite a while now, the tech world has been smitten with the Raspberry Pi.  Since it came on the scene in 2012, it’s evolution and innovation has remained widely successful when it comes to the automation of tasks.  From emulating video games, to automating private homes, to even hacking various electronics, the Raspberry Pi proves itself a dominating force in automation.  So of course the next natural step is integrating it in the industrial automation sector.

Of course there exists questions regarding implementing Raspberry Pi into automation.  “How would it be used?” “Why would anyone use it?” “What advantages does it have?” In this article we  will explore the capabilities of the tiny but mighty process board and what about it and its potential in the industrial sector.

Read more: Raspberry Pi in Industrial Automation

Raspberry Pi: A Brief Introduction

If you’re in the tech sector for whatever reason, be it profession or hobby, chances are you have encountered the Raspberry Pi at some point.  At the very least you may have heard of it.  For those who don’t know, the Raspberry Pi is commonly designated as a SBC or Single-Board Computer.  Honestly, this characterization is pretty accurate.  The main computer component of the Pi is the size of a credit card, with the enclosure, you’re looking at a device that is about the size of a pack of cigarettes.

So a small pocket-sized  computer is cool, but what does it do?  Well, surprisingly a lot of things!  Hobbyists use the Pi when working with things such as robotics. Instructors find Pi as an easy way to teach programming languages to students. For the longest time Pi has gained prominence amongst private consumers and institutions. 

However, most recently, Pi has proven itself very useful in the industrial sector as well.

The Beginning of Raspberry Pi

Raspberry Pi’s origins traces back to Cambridge University during the early 2000’s.  A group of engineers headed by Eben Upton sought ways to rekindle interests in programming among a younger generation.  Today, sites like CodeMonkey, have enough demand from children as young as five years old wanting to get into programming.  However, in the early 2000’s programming remained a niche interest that required sophisticated knowledge of computational language to do.   It existed as a far cry from the more streamlined process that we see today.

In 2006 Upton and his team set out to design a small computer no bigger than a credit card, that was widely programmable, affordable, and adaptable in running various programs. Their work finally came to fruition in 2012 with the release of the Raspberry Pi Model B.  Features on this tiny triumph included both USB and HDMI ports.  It also sported a SD card slot for storage capabilities.  Best of all it was all packaged at a price point of $35.  This made it an overnight hit with professionals, educators, and hobbyists alike. 

Integrating Raspberry Pi Into Industrial Automation

So how did this unassuming little single-board computer get the attention of the automation industry?  For starters, it’s a very affordable platform that can complete a multitude of tasks. Additionally the small size of Pi also lends to them being energy efficient.  In the industrial sector, Pi boards can be integrated into sensors and used in server units.  They can be used to help manage and control PLCs. Some independent developers have coded apps that allow a Pi board to be used as a PLC.

Arguably, the largest advantage Pi has in the industry is that it exists as a platform that is not tied to any one manufacturer and can be integrated with a wide variety of equipment. You don’t have to worry about whether it’s compatible with Schneider or Yaskawa.

A Raspberry Pi SCB sits on top of a PLC.

Interested in PLCs

MRO Electric has a number of PLCs in stock available. Access the catalog here. For more information a sales representative can be reached through email: sales@mroelectric.com or by phone: (800) 691-8511. We also offer repair services.

The Role of Contactors

In industrial automation, the significance role contactors play gets overlooked. These unassuming yet pivotal components orchestrate the machinery and processes within manufacturing worldwide. From controlling motors to managing power distribution, contactors play a fundamental role in ensuring seamless operations across various industrial sectors.

Read more: The Role of Contactors

What is a Contactor?

At its core, a contactor exists as an electromechanical switch designed to control an electrical circuit. Unlike conventional switches, which operate manually, contactors primarily become utilized in scenarios where automated control is essential. They consist of a coil, which when energized, generates a magnetic field. This field attracts a movable armature, causing electrical contacts to close or open.

Contactor Applications in Industrial Automation

  1.  Motor Control: Contactors find extensive use in motor control applications. In industrial settings, contactors serve as the gateway for starting, stopping, and reversing motor operations. By effectively managing the flow of electrical power, contactors ensure smooth and precise control over motor functions. This contributes to enhanced productivity and safety.
  2. Power Distribution: Efficient power distribution is critical for maintaining operational integrity within industrial facilities. Contactors facilitate this by enabling the selective routing of electrical power to different equipment and processes. Acting as switches for high-power circuits, contactors ensure power being directed only where and when needed. This optimizes energy utilization and minimizing wastage.
  3. Heating and Lighting Control: Contactors also play a vital role in managing heating and lighting systems within industrial environments. They regulate the supply of electricity to heaters, lighting fixtures, and other auxiliary devices. Ultimately, contactors contribute to creating optimal working conditions while simultaneously conserving energy and reducing operational costs.

Advantages of Contactors in Automation

  1. Reliability: Companies build contactors to withstand the rigors of industrial environments, ensuring dependable performance even under challenging conditions.
  2. Scalability: Whether controlling a single motor or orchestrating complex automation networks, contactors offer scalability, making them suitable for diverse industrial applications.
  3. Safety: With features such as overload protection and arc suppression, contactors enhance operational safety by mitigating the risk of electrical faults and hazards.
  4. Remote Control: Advanced contactor systems are integrable into broader automation frameworks, allowing for remote monitoring and control of industrial processes. This greatly improves operational efficiency and responsiveness.

Challenges and Innovations

While contactors have long been integral to industrial automation, ongoing advancements in technology continue to shape their evolution. Miniaturization, enhanced efficiency, and integration with digital control systems are just some of the areas witnessing innovation within the realm of contactor functionality. Moreover, the advent of predictive maintenance techniques empowered by artificial intelligence promises to further optimize the reliability and performance of contactor systems, minimizing downtime and maximizing productivity.

In Need of Contactors?

.MRO Electric offers a variety of contactors well-suited for your automation needs. For more information on contactors send an email to sales@mroelectric.com or call (800) 691-8511. Read more information on components of industrial automation equipment, here.


 From motor control to power distribution, their versatility and reliability make them indispensable assets across a spectrum of industrial applications. As technology marches forward, the evolution of contactors continues, poised to further elevate the efficiency, safety, and scalability of automated systems in the years to come.

Components of a PLC

Programmable Logic Controllers (PLCs) play a crucial role in controlling and monitoring various processes. PLCs are versatile devices designed to automate electromechanical processes, replacing traditional relay-based control systems. Understanding the key components of a PLC is essential for engineers and technicians working in automation. Generally, four main components that make up a PLC.

Read more: Components of a PLC

What is a PLC

In the past we’ve covered PLC’s and what they are, as well has how they function.  The basic run down of a PLC is that it  is a specialized industrial computing device designed to control and automate various processes within manufacturing and industrial environments. It serves as the brain of an automated system, executing programmed instructions to manage machinery, production lines, and other electromechanical processes. PLCs offer flexibility and versatility, enabling engineers and technicians to modify and adapt control logic easily without the need for extensive rewiring or hardware changes.

At the core of a PLC is its Central Processing Unit (CPU), responsible for executing control programs stored in memory. The CPU reads and interprets the instructions, making decisions based on the programmed logic. It then sends signals to output devices such as motors, valves, and sensors. Input modules gather data from the field through various sensors and switches, converting analog or digital signals into a format that the PLC can comprehend. Conversely, output modules translate the processed information from the CPU into signals that control the physical components of the automated system.

The Four Components

Central Processing Unit (CPU)

At the heart of every PLC is the Central Processing Unit (CPU). This component is the brain of the PLC, responsible for executing control programs and processing inputs and outputs. The CPU reads the program from memory, interprets the instructions, and sends signals to the output devices based on the program’s logic. Modern PLCs come with powerful CPUs capable of handling complex control tasks and communication with other devices on the industrial network.

Input Modules

Input modules are responsible for interfacing the PLC with the external world by collecting data from various sensors and switches. These modules convert analog or digital signals from field devices into a format that the PLC can understand. Digital input modules handle binary signals (on/off). In contrast, analog input modules process continuous signals such as voltage or current. Input modules are crucial for monitoring the state of the controlled system and providing real-time feedback to the PLC’s CPU.

Output Modules

Output modules facilitate communication between the PLC and the external devices such as motors, valves, or actuators. These modules convert signals from the CPU into a form that can control the physical processes in the industrial environment. Just like input modules, there are digital output modules for binary control and analog output modules for continuous control. The accuracy and reliability of output modules are vital for ensuring that the controlled system responds appropriately to the PLC’s commands.


PLCs have two types of memory: RAM (Random Access Memory) and ROM (Read-Only Memory). RAM is used for storing the control program and data temporarily while the PLC is powered on. ROM contains the firmware and the operating system that are essential for the PLC’s functionality. The memory capacity of a PLC varies, and it is crucial to choose a PLC with sufficient memory to accommodate the complexity of the control program and the amount of data processing required.


Programmable Logic Controllers have revolutionized industrial automation, providing a robust and flexible solution for controlling and monitoring complex processes. Understanding the four main components of a PLC – CPU, Input Modules, Output Modules, and Memory – is fundamental for anyone working in the field of industrial automation. As technology advances, PLCs continue to evolve, incorporating new features and capabilities. Furthermore PLCs enhance their role in modern manufacturing and industrial processes.

Whole House Surge Protectors: Pros and Cons

In today’s technology-driven world, our homes are filled with a plethora of electronic devices, appliances, and smart technologies. These advancements bring convenience and efficiency, but they also make our homes more vulnerable to power surges. A sudden surge in electrical voltage can damage or destroy electronic equipment. This leads to expensive repairs and replacements. For this reason, whole house surge protectors are an essential line of defense.

Read more: Whole House Surge Protectors: Pros and Cons

What Happens During a Power Surge

A power surge is a rapid and temporary increase in voltage that exceeds the standard flow of electrical current in your home’s wiring. These surges can result from various sources like, lightning and power grid fluctuations. While minor surges may go unnoticed, repeated exposure to these events or a severe surge can cause irreparable damage to sensitive electronics.

What Goes Into a Whole House Surge Protector

The device on the right is an example of a whole house surge protector.

Whole house surge protectors are advanced devices designed to safeguard your entire home from power surges. Unlike individual surge protectors that you plug into outlets, whole house surge protectors are installed at your main electrical panel. Their primary purpose is to intercept and divert excess voltage away from your home’s wiring. This ensures sensitive electronic devices receive a consistently safe level of power.

The Pros of a Whole House Surge Protector

  1. Comprehensive Protection: Whole house surge protectors safeguard all appliances and devices connected to your home’s electrical system.
  2. Increased Device Lifespan: Whole house surge protectors extend the lifespan of electronic devices, reducing the need for costly replacements.
  3. Ease of Installation: Professional electricians can install whole house surge protectors directly into the main electrical panel fairly easily.
  4. Fire Prevention: Whole house surge protectors contribute to fire prevention by mitigating the potential for electrical overloads that could lead to fires.
  5. Insurance Benefits: Some insurance providers may offer premium discounts to homeowners who install whole house surge protectors, recognizing the reduced risk of electrical damage.
  6. Appliance Compatibility: Whole house surge protectors are compatible with all appliances and devices connected to your home’s electrical system, ensuring consistent protection throughout the house.

The Cons of Whole House Surge Protector

  1. Initial Cost: Whole house surge protectors have a higher upfront cost compared to individual surge protectors. However, this cost may be offset by the comprehensive protection they offer.
  2. Professional Installation: Installation of whole house surge protectors typically requires a licensed electrician, adding to the overall cost. Attempting DIY installation without the necessary expertise can lead to safety hazards and ineffective protection.
  3. Limited Protection from External Sources: While whole house surge protectors are effective against internal surges originating from within the home, they may provide limited protection against extremely powerful external sources, such as a direct lightning strike.
  4. Maintenance and Replacement: Surge protectors, like any electrical device, may require periodic maintenance or replacement to ensure optimal performance. This can result in additional costs over time.
  5. Not a Guarantee Against All Surges: While whole house surge protectors significantly reduce the risk of damage from power surges, they cannot guarantee absolute protection against all types of surges or catastrophic events.
  6. Compatibility with Older Wiring: In some cases, homes with outdated or incompatible wiring may face challenges in integrating whole house surge protectors. Upgrading the wiring may be necessary for optimal functionality.
  7. Limited Effectiveness in Certain Scenarios: In extremely severe cases, such as a direct lightning strike on the power lines, whole house surge protectors may not provide complete protection. However, they can still offer a substantial level of defense in many situations.


Before investing in a whole house surge protector, it’s essential to weigh these pros and cons based on your specific needs, budget, and the electrical characteristics of your home. Consulting with a professional electrician can help determine the most suitable surge protection solution for your circumstances.

Unraveling Motor Spindle Speeds

When talking about motor spindles and CNC in industrial automation, it is natural to think that speed is the important thing to emphasize.  After all, a lot of industrial automation centers around large scale production who’s business model involves getting things made quickly.  However, speed has proven to not be the sole factor in efficient production. Varying tasks requires different speeds to complete them.  Furthermore, what speed works for one task does not necessarily work for another.

Read more: Unraveling Motor Spindle Speeds

Varying Speed Advantages

A VFD is used to control the speed of spindle motors.

Today it is very commonplace for CNC machines to run varying speeds depending on what task needs completing. Different speeds come with different advantages when dealing with motor spindles completing specific jobs. As a result, CNC machines needs to have complete variable control.

Slow Speed

In applications where precision is paramount, low motor spindle speeds are often preferred. This is particularly true in industries like aerospace and medical manufacturing, where intricate parts require meticulous machining. Low speeds also, allow for precise material removal, reducing the risk of damage to delicate components. This is crucial in applications such as milling, drilling, and engraving.

Medium Speed

Medium spindle speeds find their place in applications that require a balance between precision and efficiency. Industries like automotive manufacturing often benefit from medium-speed machining processes. These speeds are suitable for a wide range of materials and can handle various cutting tools effectively. Medium speeds are commonly employed in generic tasks like turning, threading, and grinding.

High Speed

High-speed motor spindles are the driving force behind highly productive manufacturing processes. Industries focused on mass production, such as electronics and consumer goods, rely on high-speed machining for efficiency. Rapid material removal rates and reduced cycle times make high spindle speeds ideal for tasks like milling, drilling, and routing. The ability to process materials quickly without sacrificing quality is a key advantage in these applications.

The Need for Variable Speeds

Spindle motors running at low speed are ideal for precise task, such as engraving.

Many modern CNC machines feature variable-speed motor spindles, allowing for dynamic adjustments based on specific requirements. This adaptability is particularly beneficial in environments where multiple materials or machining processes are involved. Variable speeds enable operators to optimize performance for different tasks within a single machining operation, enhancing overall efficiency and reducing setup times.

Motor spindle speeds also play a crucial role in managing heat generation during machining. In some applications, especially those involving hard materials, excessive heat can lead to tool wear and reduced tool life. Adjusting spindle speeds allows for better control over the heat generated during machining, promoting longer tool life and maintaining the integrity of the machined components.


In conclusion, the diverse motor spindle speeds available in industrial automation provide a spectrum of options for manufacturers to tailor their machining processes to specific needs. Understanding and effectively controlling motor spindle speeds are essential for optimizing manufacturing operations in industrial automation today. As technology advances, the integration of smart systems and real-time monitoring will further enhance the efficiency and adaptability of motor spindle speed control in industrial automation.

MRO Electric has a complete inventory of new motor spindles and VFDs. Please call 800-691-8511 or email sales@mroelectric.com for pricing and information. MRO Electric also offers repairs and replacement jobs.

Components and Functions of a CNC Machine

Since the mid-twentieth century Computer Numerical Control (CNC) machines have revolutionized the manufacturing industry. They have done so by automating and enhancing precision in the production of various components. Industries that often use them include aerospace, automotive, and electronics to create intricate and accurate parts.

Read more: Components and Functions of a CNC Machine


A CNC machine is basically a sophisticated tool that translates digital instructions into precise physical movements. It allows the user to interface with

The primary functions of a CNC machine include:

  1. Digital Control: Computer programs that dictate the tool’s movements and actions. These programs contain detailed instructions for the machining process.
  2. Automated Precision: One of the key advantages of CNC machines is their ability to execute repetitive tasks with unparalleled precision. The automation eliminates the margin of error associated with manual operations, resulting in consistently high-quality products.
  3. Versatility: CNC machines can perform a wide range of tasks, from cutting and milling to drilling and engraving. Their versatility makes them indispensable in various manufacturing processes.


The roots of CNC technology can be found in the development of numerical control systems during the mid-twentieth century. Around this time, the aviation industry emerged as a significant catalyst for CNC innovation. Engineers sought a more efficient and precise way to machine complex components for aircraft. This led to the birth of numerical control as a solution to automate machine tools.

Early example of a CNC Machine

The 1940’s kicked off the history of the CNC machine with the introduction of punched tape systems. These systems allowed engineers to input numerical instructions into machine tools, automating certain aspects of the machining process. It wasn’t until the 1950s that the concept of CNC truly began to take shape. John T. Parsons, often regarded as the father of CNC, played a pivotal role in advancing the technology. Parsons, along with Frank L. Stulen, developed the concept of controlling machine tools through punched cards, laying the groundwork for the CNC machines we know today.

During the 1960s, the Massachusetts Institute of Technology (MIT) introduced the concept of direct numerical control (DNC). As the technology matured, industries beyond aviation started adopting CNC machines. The 1970s saw the integration of computers into CNC systems, allowing for more sophisticated programming and control. This integration, allowed the machines to become increasingly versatile and accessible. This led to widespread CNC adoption across various manufacturing sectors.

Example of modern CNC machine. Note the digitalized control panel

CNC machines evolved beyond milling to encompass a wide range of machining operations. This includes turning, grinding, and electrical discharge machining (EDM). Presently, CNC machines are at the forefront of advanced manufacturing, shaping industries ranging from automotive and aerospace to electronics and healthcare.


While there are varying models and designs, CNC machines generally are made of several different parts. These parts are crucial to the function of the CNC.

  1. Control Unit:
    • Computer: The brain of the CNC machine, the computer processes the instructions from the program and translates them into electrical signals.
    • Control Panel: Operators use the control panel to input data, set parameters, and monitor the machine’s performance.
  2. Drive System:
    • Motors: Drives the movement of the cutting tool along the specified path. Common types include stepper motors and servo motors.
    • Ball Screws/Rack and Pinion: These components convert the rotational motion of the motors into linear motion, guiding the tool precisely along the desired path.
  3. Tooling System:
    • Cutting Tool: The cutting tool is an essential component that physically shapes the material. Different tools are used for various machining operations.
    • Tool Changer: In machining processes that require multiple tools, a tool changer automates the process of switching between tools.
  4. Work Holding Device:
    • Vise or Chuck: The workholding device secures the raw material in place during machining. It ensures stability and accuracy throughout the cutting process.
  5. Coolant System:
    • Coolant Tank and Pump: Machining generates heat, and a coolant system helps dissipate this heat, preventing damage to the tool and workpiece. It also aids in chip removal.
  6. Axis System:
    • Linear Guides: These guides facilitate the smooth movement of the machine’s axes. They play a crucial role in maintaining accuracy during machining.
    • Axis Motors: CNC machines typically operate in three or more axes (X, Y, Z), and each axis has its motor for precise control.


Understanding the functions and components of a CNC machine is essential for those involved in the design and operation of these advanced manufacturing tools. As technology continues to advance, CNC machines are likely to play an even more pivotal role in shaping the future of manufacturing processes.