Determining Encoder Selection

What is the role of the encoder?

For any motion control process to work, a sensing device is needed to provide reliable feedback sensing. The encoder is the part of the machinery that furnishes feedback information. How does the encoder work? The encoder receives a motion signal and converts this signal into an electrical signal that can be read by some sort of motion control system, like a PLC. The motion control system then uses the signal to control conditions such as speed, direction, and position on your machinery.  This process is consistent in any application: The exchange of information between the machine and the controller through the encoder signaling generates the exact performance function.

“The core function of the encoder is to provide information about the motion of the moving parts in your system.”

Adam Gross, Lead Technician, MRO Electric

Selection requirements

What do you need to know when choosing an encoder that is right for your application? There are a couple of fundamental points when selecting which encoder is correct for the job. 

When selecting an encoder, one thing you will need to determine is the application control specifications. Applications can range from very simple machine applications to complicated machinery. Some applications are simple and require simple position or speed control with a low degree of accuracy needed, while more sophisticated machinery may need a higher level of feedback. Knowing the application of the encoder is vital in the selection process.

Another thing to consider is the encoder properties. Typically, this involves the number of rectangular pulses per motor revolution. A pulse number is delivered by two channels. The two channels have a phase shift of one-quarter of a pulse length, sometimes referred to as quadcounts. In this way, motor rotation direction can be detected using the four distinct states per single pulse. These four pulses represent the real resolution. For instance, if an encoder has 2,000 counts per pulse term; it gives 8,000 states per turn, which determines a nominal resolution of 360/8000=0.045°. Encoders detect motion encompassing a wide range of counts per turn. That means you must decide whether your application requires a simple encoder with fewer CPT or a more complex encoder that can detect an extremely accurate position or speed. 

Other factors can impact resolution. The mechanical layout is a consideration for encoder resolution as well as other influences like analog or digital signals. Underlying physical foundations like optical, magnetic, or inductive principles can also play a part in encoder resolution. 

Exposure to specific environmental elements factors into selection consideration as well. The encoder may require a shield if it is in an environment where it is likely to be exposed to conditions such as dust, moisture, or corrosive chemicals. Encoders are susceptible to environmental extremes such as temperature, shock, or vibration.

Encoder Types

A simple approach to guide your determination in encoder options is to characterize the type of movement the encoder is monitoring. There are three commonly used encoders: Linear, rotary, and angle encoders.

 The linear encoder is an encoder that senses the movement of linear objects to encode position.  A scale is determined that allows the sensor to convert the encoded position into a signal that could be analog or digital. The signal can then be decoded into a position by a motion control system. Machining tools use the linear encoder to coordinate measuring machines, such as a cut length application. In cut-length applications, the control device and encoder determine how much of a particular item, such as cloth material, is fed through the machinery, measuring where to cut. Sometimes a cable is run between an encoder and a moving object, using a transducer to produce an analog or digital output signal to establish the movement or position of the object.

For rotating objects, a rotary encoder is used. Providing feedback about the movement of a rotating object or device, a rotary encoder converts the angular position of the moving shaft into an analog or digital output signal. This signal is used to allow a control system to determine the position or speed of the shaft. Rotary encoders can be mounted directly to a motor or any machinery with a rotating shaft and are sometimes called shaft encoders. The two main types of rotary encoders are the absolute encoder and the incremental encoder.  What is the difference between the two? The difference is in the output.

The absolute encoder indicates the current shaft position, while the incremental encoder provides information about the motion of the shaft. The Absolute encoder is an angle transducer, whereas the incremental encoder typically processes information such as speed, position, and distance. Applications for the rotary encoder involve such things as robotics and industrial controls, which require monitoring and/or control.

Angle encoders are like rotary encoders; however, they are more apt to offer higher accuracy. It measures the angular position of a rotating shaft. A disc-shaped rotator uses an optical grating that operates with an optoelectric sensor on the stator. Because optical technology is dependent on the tightly constrained rotation of the rotor in relation to a stator, an angle encoder is used to keep the two parts concentric using bearings.

Encoders have the potential to elevate performance and increase productivity through their sensing technology. Selection consideration includes many aspects, some of which are presented above. For a closer look at the encoders offered at MRO Electric, please visit our website, or give us a call.

Product Spotlight: Square D EDB34030 Circuit Breaker

The Square D EDB34030 is a three pole, 30 Ampere circuit breaker. At 277V, this miniature breaker is reliable, sustainable, efficient and safe.

Part Number: EDB34030
Item Weight: 3.6lbs
Product Dimensions: 9.7 x 6.1 x 4.5 inches
Voltage: 480V
Amperage: 30A
Trip Rating; 875A
Mounting Mode: Bolt-on
Interruption Rating: 18kA

Square D EDB breakers by Schneider Electric are available in a range of amperages varying from 20A to 60A. This particular model, the EBD34030, is 30A.
This breaker is set apart from other breakers because of its compact size at 9.7 x 6.1 x 4.5 inches, while the typical breaker is around 8 x 8 x 12 inches. As a bolt on mount, it is preferred in commercial and industrial applications where vibrations might be considered an issue. When installing, be sure to use the recommended #12-#6 AWG AI or #14-#6 AWG Cu Lug wire. This breaker is ideal for NF series panel-boards to offer superior overload and short circuit stability by utilizing thermal magnetic protection. It is also HACR rated, UL listed and CSA certified.

MRO Electric and Supply stocks Square D circuit breakers, including the EDB34030. For more information or to request a quote, please contact us at 800-691-8511 or at sales@mroelectric.com.

Kawasaki E3/E7/E9 Controllers

Being a leader of the robotics industry for over 50 years, Kawasaki has developed one of the most complete lines of e-controllers on the market. All of these controllers are suited with a wide array of features including:

  • High powered CPU performence
  • Large, easy to use LCD Display
  • Optimized key layout
  • Easily accessible safety switches

The E76/77 family of controllers are very compact and used for smaller robot arms. One of these arms are the RS003N Robot, which has a maximum payload of 3kg and has horizontal and vertical reaches of 620mm and 967mm, respectively. The controllers with these robots specialize in assembly and material handling applications.

The E9 family of robotic teach pedants are also built very compact, however these devices are typically used in medium-duty applications. Unlike the other two families of controllers, the E9 family features an open structure system with a direct cooling system. However, like the E7 and E3 families, the enclosed structure with indirect cooling is an available option. The E9 family takes full advantage of the digital servo drive powering it to have a maximum payload capacity of 40kg.

E30/32/33/34 controllers at their base are very alike the E76/77 controllers but with more power. These devices are not as compact as the previous devices we have discussed, however the reason being they are highly expandable and are easier to maintain. Features such as Kawasaki’s K-Logic sequencer software allow the addition of up to 16 total controllable axes. The E3 family of Kawasaki e-controllers are able to handle the following maximum payloads:

  • E30 – 145 kg
  • E32 – 180 kg
  • E33 – 195 kg
  • E34 – 180 kg

If you are interested in learning how to purchase the robot arm, the controller, or any other part/device that goes into an industrial robotic set-up, please call MRO Electric and Supply at (800)691-8511 or email us at sales@mroelectric.com and we will help you get what you need.

3HAC028357-001

ABB Robotics 3HAC028357-001 Teach Pendant

The 3HAC028357-001 is a modern ABB Robotics Teach Pendant designed to be used with the IRC5 Industrial Robot Control, one of the most popular robotics controls on the market. Also known as the “FlexPendant”, the 3HAC028357-001 is characterized by its clean, color touch screen-based design and 3D joystick for intuitive interaction.

The 3HAC028357-001 TPU (or teach pendant unit) is a hand held operator unit used to perform many of the tasks involved when operating a robot system: running programs, jogging the manipulator, modifying robot programs and so on.

The FlexPendant is designed for continuous operation in harsh industrial environment. Its touch screen is easy to clean and resistant to water, oil and accidental welding splashes.

ABB FlexPendant

The 3HAC028357-001 replaces the legacy 3HAC023195-001 teach pendant.

The standard cost for a new ABB 3HAC028357-001 direct from the manufacturer or authorized distributor is typically in the $6000-7,000 range. MRO Electric is able to supply these pendants at a much lower price point, and we warranty all of our robotics parts for 12 months.

If you would like a free quote on a replacement ABB 3HAC028357-001, please email us at sales@mroelectric.com or call 800-691-8511.

Siemens Sinamics DME20 Hub Module: Beyond the User Manual

The Siemens SINAMICS DME20 DRIVE-CLiQ Hub Module is used to implement a star-shaped topology of a DRIVE‑CLiQ line. Two DME20 DRIVE‑CLiQ Hub Modules can be connected in series. Signals from more than one encoder can be collected with one DRIVE-CLiQ Hub Module and forwarded to the Control Unit through a single DRIVE-CLiQ cable. The Siemens SINAMICS DME20 is used to connect direct measuring systems for the feed axes and expansion axes of the S120 Combi.

dme20

The DME20(6SL3055-0AA00-6AB0) DRIVE-CLiQ hub module offers the following features:

  • 6 DRIVE-CLiQ sockets for connecting up to 5 more DRIVE-CLiQ modules
  • 1 connection for the power supply module via 24V DC circular supply connector
  • 4 x 0.75 mm pins (pins 1 and 2 are bridged, along with pins 3 and 4)

The SINAMICS DME20 uses the Siemens STARTER software to parameterize and commision drive units. The STARTER commissioning tool can be used for commissioning, testing through a control panel, drive optimization, diagnosing drives, and setting up and running built in safety functions. The tool offers support for various operating wizards, running trace functions to optimize drive controllers, creating and copying data records, loading projects from the programming device to the target device(and vice-versa), along with so much more.

Does your Siemens SINAMICS DME20 hub module need to be serviced? As with all of our services, our repairs come with a 12 month guarantee. Our repair service is based on doing the right job, and getting your part back to you as soon as possible. Every part we refurbish is tested to make sure they work the way they are supposed to. Our factory-trained technicians have many years working with Siemens products. Minimize your future downtime today by contacting MRO Electric and Supply right now.

For a free repair quote on DME20 hub modules, please email sales@mroelectric.com or call 800-691-8511.  For more information on our Siemens repair capabilities, you can visit our Siemens Repair page.

Siemens Sinamics GM150: Beyond the User Manual

The SINAMICS GM150 is a universal single-motor drive for applications involving square-law and constant load characteristics without regenerative feedback into the line supply. These drives are especially suited for pumps, fans, compressors, mixers, crushers and ships. Simplicity of the Siemens SINAMICS GM150 variable speed drives is due to the use of standardized engineering tools such as SIZER and STARTER. Some of the advantages of the GM150 include:

  • Power ratings from 9 MW to 27 MW
  • Induction and synchronous motors
  • Integrated maintenance functions
  • Factory-tested interaction between motor and drive
  • Simple integration into existing automated system
  • Compact design with highly flexible configuration
  • Top tier toughness due to HV-IGBT/IGCT technology with a fuseless design
  • Designed to handle both air and water cooling

gm150

The drive units are equipped with maintenance functions that tries to prevent faults by fixing them before they happen. The drive will send signals when it knows that a part will need to be fixed or replaced. With a high degree of flexibility when it comes to connections and mounting, Siemens GM150 and SM150 systems have very user friendly operator panels for the easiest operator control and visualization. Reliability is key in any automated system.

Does your Siemens SINAMICS GM150 module need to be serviced? As with all of our services, our repairs come with a 12 month guarantee. Our repair service is based on doing the right job, and getting your part back to you as soon as possible. Every part we refurbish is tested to make sure they work the way they are supposed to. Our factory-trained technicians have many years working with Siemens products. Minimize your future downtime today by contacting MRO Electric and Supply right now.

For a free repair quote on GM150 modules, please email sales@mroelectric.com or call 800-691-8511.  For more information on our Siemens repair capabilities, you can visit our Siemens Repair page.

Looking Inside the Siemens Sinamics CU305, CU310-2, and CU320-2

Electronically coordinated single-motor drives work in unison to perform your all of your drive needs. In multi-axis drives, the individual drives are controlled from a higher-level control system in a way to achieve the desired coordinated movement. A centralized Siemens SINAMICS Control Unit has control over the drives for all connected axes and also establishes the links between the drives and/or axes. Since all required data is stored in the central Control Unit, it does not need to be transferred. The CU310-2 is used in conjunction with power modules and single-motor drives whereas the CU320-2 is used with all motor modules or line modules for both single and multi-motor drives.

Different versions of these control units include:

All of these control units are based on an object-oriented SINAMICS software called SIMOTION. The firmware included contains all common control modes and can be scaled to meet almost all automation requirements. This firmware will contain instructions for infeed controls for main infeeds, and all vector an servo controls.

Does your Siemens SINAMICS CU305, CU310-2, or CU320-2 control unit module need to be serviced? As with all of our services, our repairs come with a 12 month guarantee. Our repair service is based on doing the right job, and getting your part back to you as soon as possible. Every part we refurbish is tested to make sure they work the way they are supposed to. Our factory-trained technicians have many years working with Siemens products. Minimize your future downtime today by contacting MRO Electric and Supply right now.

For a free repair quote on CU305, CU310-2, and CU320-2 modules, please email sales@mroelectric.com or call 800-691-8511.  For more information on our Siemens repair capabilities, you can visit our Siemens Repair page.

Looking Inside the Siemens Sinamics SME20/25 and SME10/125 Encoder

The encoder system is connected to the SINAMICS S120 via DRIVE-CLiQ. Motors with DRIVE-CLiQ interfaces are designed for this purpose. These motors simplify commissioning and diagnostics because the motor and encoder type are identified automatically. The Sensor Modules(SME20, SME25, SME120, and SME125) are only to be used with machines and may ONLY be connected to the DRIVE-CLiQ interfaces of proprietary components. Direct encoder systems outside the cabinet can be connected to the Sensor Modules External. The SMEs evaluate these encoder systems and convert the calculated values to DRIVE-CLiQ. No motor or encoder data is stored in the Siemens SMEs. The Sensor Modules External provides the encoder power supply. The power supply for the SME is provided from the connected DRIVE-CLiQ cable. This should be taken into consideration when selecting the DRIVE-CLiQ cable. SMEs have a higher degree of protection(IP67) which means it is suitable to be installed on the outside of the cabinet.

Part numbers for the SMEs include:

Below is a chart that shows the connectable encoder systems between the SMC and SME modules.

sinamics

Does your Siemens SINAMICS S120 series encoding module need to be serviced? As with all of our services, our repairs come with a 12 month guarantee. Our repair service is based on doing the right job, and getting your part back to you as soon as possible. Every part we refurbish is tested to make sure they work the way they are supposed to. Our factory-trained technicians have many years working with Siemens products. Minimize your future downtime today by contacting MRO Electric and Supply right now.

For a free repair quote on SME20, SME25, SME120, and SME125 modules, please email sales@mroelectric.com or call 800-691-8511.  For more information on our Siemens repair capabilities, you can visit our Siemens Repair page.

Siemens Sinamics PM230, PM240, and PM250: Beyond the User Manual

The Siemens SINAMICS G120 inverter has been designed for the accurate and efficient control of the speed and torque for three-phase motors. The Siemens SINAMICS G120 system comprises two basic modules, the Control Unit (CU) and the Power Module (PM).

PM230 Power Modules, are focused on the HVAC industry sector especially for pump and fan applications. The Power Modules are available with class-A filter or unfiltered in a rated power range from 0.37 kW to 90 kW and a line voltage range from 3 AC 380 V to 480 V. The PM240 Power Module comes with resistor braking and dc braking functions, and a supply voltage of 3 AC 400 V. The PM250 Power Module includes the regenerative braking function, and a supply voltage 3 AC 400 V. For the power modules, induction motors are permissible in the range from 25% to 150% of the inverter power without any restrictions. Wiring diagrams, specification datasheets, and user manuals are available on the MRO Electric and Supply website.

Some of the part numbers for these Power Supply Modules include:

240

Maintenance is needed to preserve the specified condition of the Power Module. Dirt
and contamination must be removed regularly and parts subject to wear replaced. The
Power Module comprises mostly electronic components. Apart from the fan(s), the unit,
therefore, contains hardly any components that are subject to wear or that require
maintenance or servicing.

Does your G120 Series SINAMICS power supply module need to be serviced? As with all of our services, our repairs come with a 12 month guarantee. Our repair service is based on doing the right job, and getting your part back to you as soon as possible. Every part we refurbish is tested to make sure they work the way they are supposed to. Our factory-trained technicians have many years working with Siemens products. Minimize your future downtime today by contacting MRO Electric and Supply right now.

For a free repair quote on PM230, PM240, PM250 modules, please email sales@mroelectric.com or call 800-691-8511.  For more information on our Siemens repair capabilities, you can visit our Siemens Repair page.

Looking Inside the Siemens Sinamics SMC10, SMC20, and SMC30

Siemens SINAMICS SMC10, SMC20, and SMC30 drives include high-performance single drives and coordinated drives (multiple-axis applications) with vector or servo functionalities that allow for implementation of truly customized high performance drive solutions for the ultimate in flexibility and increased productivity. In addition to an innovative system architecture and digital communication options, these drives come in a variety of designs and cooling types, each delivering performance from 0.16 to 6,000 HP, and feature efficient engineering and quick commissioning resulting from innovative tools and simple wiring. The SINAMICS series is built to be as streamlined with your automation operations as possible. Different Siemens SINAMICS S120 versions can be combined as required through the DRIVE-CLiQ interface.

A few of the popular modules for the SINAMICS S120 series of drives are the SMC Sensor Modules. The cabinet-mounted sensor module is necessary to evaluate the encoder signals of motors without  a DRIVE-CLiQ interface.

Part Numbers:

  • SMC10 – 6SL3055-0AA00-5AA3 Used for determining the actual motor speed and the rotor position angle
  • SMC20 – 6SL3055-0AA00-5BA3 Used for determining the actual motor speed and the path length
  • SMC30 – 6SL3055-0AA00-5CA2 Used for determining the actual motor speed

smc10

The SMC10/20/30 Sensor Modules feature the following connections and interfaces:

  • 1 encoding connection including motor temperature sensing via SUB D-connector
  • 1 DRIVE-CLiQ interface
  • 1 power supply connection (24 V DC connection)
  • 1 PE connection

Has your S120 Series SINAMICS module failed? As with all of our services, our repairs come with a 12 month guarantee. Our repair service is based on doing the right job, and getting your part back to you as soon as possible. Every part we refurbish is tested to make sure they work the way they are supposed to. Our factory-trained technicians have many years working with Siemens products.

For a free repair quote on SMC10, SMC20, SMC30 modules, please email sales@mroelectric.com or call 800-691-8511.  For more information on our Siemens repair capabilities, you can visit our Siemens Repair page.