In this Ask the Expert feature, Siemens’ SIMOCODE expert, Mark Berger, provides a thorough introduction to motor control and motor management solutions, addressing topics including application areas and key characteristics and comparing and contrasting Siemens’ SIMOCODE solution with competing alternatives.
In this latest installment of RS’s Ask the Expert Series, Mark Berger, the circuit protection and controls business product developer at Siemens, provides a thorough introduction to motor control and motor management. He addresses how motor control factors into machine safety, the types of applications constant-speed, low-voltage motors are used in, the primary components of a low-voltage motor control system, three key characteristics of an effective motor control system, the difference between motor control and motor management, the unique benefits these systems provide and the applications they’re most beneficial in and what makes Siemens’ approach to motor management and control systems unique compared with competing solutions.
Hi Mark. How did you come to work in motor control and machine safety, and what do you find most interesting about this segment of the electronics industry?
I earned a degree in applied physics while working as an electrical engineer at an aviation and aerospace company and then got a job as a controls engineer at a company that specializes in metal fabrication and machining. That job introduced me to the motor control and automation industry, and the four years of experience I gained there paved the path to my current position as Siemens’ circuit protection and controls business product developer.
When I got hired in 2006, my boss handed me several feet of inch-thick product catalogs and said to find a product I have a passion for and hold onto it. That’s when I stumbled across SIMOCODE. I’d never heard of it before, even though it had launched in 1996 and had already had one generational change, but the more I learned about it, the more convinced I was that it’s one of the top — if not the top — motor control and motor management solution available on the market due to its unique capabilities, and I still feel the same about it more than 15 years later. In my previous role, I’d been using a combination of devices to provide the same protection that SIMOCODE provided in a small, precise package that’s flexible enough to do anything I would have needed it to do, regardless of the process it’s installed in. So, I made it my mission to introduce SIMOCODE to anyone who could possibly benefit and am proud to have helped countless customers achieve critical safety and performance improvements by integrating these innovative solutions into their processes.
The things I enjoy most about the motor control and machine safety industry are the many different challenges it presents and how quickly enabling technology evolves. There’s really a wow factor compared to the old days in terms of technological improvements, as well as cost effectiveness and efficiency. I also really enjoy that every day is different even with I’m working with the same equipment. There’s always a new opportunity to identify the best places to invest time, effort and expense to increase machine availability and capabilities and to identify additional applications we can improve upon as well.
How does motor control factor into machine safety?
In most cases, motor control devices are used to control a motor that controls a process, like a blade, pump or fan, that operators or another machine interact with. Depending on the safety level of the hardware or the machine you’re working with, machine safety systems can keep the machine from damaging itself or the process, as well as protect the operators that interact with the machine. Motors are everywhere you turn, and they can cause harm to a person or another machine, so it’s important to follow the plant specifications and requirements for safety and to employ flexible control systems capable of both ensuring machine and operator safety and protecting the process.
What types of applications are constant-speed, low-voltage motors used in?
Constant-speed, low-voltage motors are used in any application with a turning medium, like blades. Standard applications span the industrial, utilities, and mining industries and include water, wastewater, and pumping systems, conveyor systems, air exchangers with fans, and rock crushing equipment used to pulverize material into a powder. For instance, I’ve got a process customer in Wyoming that takes trona (which looks like quartz), pulverizes and refines it into a powder called soda ash, stores it in a big tank, adds process water to liquify it, and then merges it with other chemicals to make things like laundry detergent, household cleaning products, and kitty litter.
What are the primary components of a low-voltage motor control system?
The most basic motor control systems, like those used pump panels or motor stop/start stations, have a push button for stop/start or hand-off auto (HOA) functionality and a motor contactor with overload protection to prevent the motor from overheating.
Higher-end motor control systems typically have an HMI touchscreen for ease of use and a PLC that allows users to add more control functionality, like phase loss and balance monitoring to protect the motor at the voltage sensor rather than the current sensor, a vibration sensor to protect the motor from misalignment and auxiliary temperature monitoring equipment to protect the gearbox, pump and motor from overheating or, in a conveyor system, to keep the pillow block bearings or pully system from overheating. If a bearing starts to show friction, it increases the motor current draw to continue turning the conveyor belt, or the pump or what have you, and that increased current increases motor heat, which causes other problems since heat is the enemy of electronics. In a higher-end motor control system capable of monitoring motor current and bearing temperature, an overload in the standard motor stop/start circuit used to monitor the current draw will make the motor contactors trip at a certain level to prevent the motor from overheating.
What are the top three key characteristics of an effective motor control system?
Protection, monitoring and controlling. Effective motor control systems reliably protect motors from overload and loss of phase or phase imbalance, which means that one of the three phases is no longer helping the motor turn properly. They also offer advanced monitoring capabilities that provide operators with data including how many times the motor has been turned on and off and whether there are any other outside influences, like if the motor came unbolted or if it’s misaligned or vibrating. The controlling characteristic has to do with process control, such as the ability to say that a motor only needs to run four times a day or that it only needs to be started once or twice a day, or to quantify the number of times that a motor stops and starts to help operators realize why the motor isn’t turning and, in turn, why their profit goals may not be met.
What is the difference between motor control and motor management?
Motor control is the scenario-based control of when the motor should be turned on or off depending on the upstream or downstream processes that call for it. Simple on/off control decisions, like for a small pump controller with no hierarchical control system, can be made locally using internal logic. More complex pump controls are turned over to a PLC or a distributed control system. But SIMOCODE has the power and flexibility to protect and control any motor and optimize any processes — no matter how simple or complex — in accordance with the input data.
Motor management is the next level of data. It’s knowing how long a motor has been turned on and using that data to schedule predictive maintenance rather than reactive or preventative maintenance. Reactive maintenance is reacting to an issue you’re made aware of as it’s happening. This type of maintenance results in unplanned downtime and productivity and profit losses. Preventative maintenance is a day on the calendar, like a note to stop and grease a motor six months after it was last maintained. And that sounds like a good plan, but without motor management data, like its duty cycle, there’s a chance that motor only got turned on five times and ran for fewer than 50 hours in those six months. So, taking that motor offline and investing in maintenance labor and parts, like a new motor contactor, just because it’s six months to the day after it was last maintained isn’t an efficient use of company time and money.
The best maintenance is predictive maintenance based on motor management data like duty cycle reports that let operators know when a motor has been started a given number of times, say 600 times, since it was last maintained. Operators can see that number slowly ticking up to the limit, order the parts they’d like to replace as far in advance as they’d like and already have them on-hand to help reduce downtime when the maintenance limit is reached. In this case, operators would still know that the limit is arriving and be able to plan for the downtime and, when it was reached, could stop the motor, check its electrical and mechanical connections and consider replacing the motor starter (the contactor) that supplies power to the motor to prepare it for another 600 starts.
SIMOCODE gives you all the tools you need to control and manage your motor, as well as to optimize your processes and enable predictive, cost-controlled maintenance. It has a user-friendly HMI that allows operators to easily define parameters like, “Let me know when this motor has run for 600 hours or started 600 times,” and a logic component that monitors data to ensure optimal operation and efficiency. For instance, if you have a motor starter that requires hundreds of Amps, you’ll want to make sure that motor only starts once or twice a day and then stays running to avoid a continual inrush of high current to maximize energy efficiency. SIMOCODE’s monitoring capabilities can identify any performance deviations that could cause disruptions or require additional starts and alert operators to that potential before it happens so steps can be taken to prevent it.
I once had a SIMOCODE customer call me after their third motor contactor — which is a big, expensive part that takes two to three hours of downtime to replace — burned up. I went out to help him and, using the SIMOCODE’s internal logic, added a rule restricting the motor to a maximum of three starts per half hour since the product of the inrush current required to start the motor is heat and excess heat is what’s burning up the starter.
By adding that rule to the SIMOCODE logic, the customer quickly found out that an operator had been using that motor for something that it wasn’t made to do, which had burned up the three contactors, and was able to provide that operator with the training they needed, protecting his investment in both his machine and his employee. The SIMOCODE’s logic capabilities effectively protected the motor from a process that it wasn’t even meant to be used for and, in doing so, allowed the customer to identify a problem they had not been able to solve for weeks without that logic rule. After seeing more of the SIMOCODE’s capabilities, that customer installed many more SIMOCODE to further optimize his costs, efficiencies and processes.
What unique benefits do motor management and control systems provide, and which types of applications are they most beneficial in?
A standard motor control circuit is a stop/start circuit. You walk up and press a button to stop or start the motor. Within that simple circuit there’s also an interlock, or an auxiliary holding contact, because the pushbutton is a momentary pushbutton, which means that the motor will run while you’re pushing it, but not if you let off, so the operator can’t walk away unless that additional component is present. The auxiliary contact closes to allow you to take your finger off the button and leave the motor running, but it also adds component and wiring costs and another potential point of failure.
With SIMOCODE, you don’t need an interlock or auxiliary contactor because there’s a simple checkbox input that lets users tell the internal system logic how they want it to act and react to a start circuit. Removing that component and wiring from the system does offer some minor cost savings, but its real value is in simplifying troubleshooting and maintenance processes. If a motor with an interlock and wiring isn’t running smoothly, that’s one of the first places you’d start looking for issues. But with the SIMOCODE, you just have to read the HMI output, which could convey, for instance, that the motor starter experienced an overload event.
Motor management systems provide configurable control and monitoring functions beyond just stop/start functionality. They deliver enhanced diagnostics capabilities and ensure the full protection and functionality of motor starters even if the control system or bus system fails. They also maximize efficiency, leading to optimal utilization and long-term stability, and because they have flexible software- versus hardware-based motor controls, they’re more modular and flexible than standard motor control systems as well.
Higher-end motor control and management systems like SIMOCODE also have OPC Unified Architecture (OPC UA) built in at no additional cost. OPC UA is a generic communications protocol that’s used as a universal translator for manufacturing equipment. It allows the SIMOCODE to transmit motor status notifications to both Siemens and non-Siemens equipment so the data can be used throughout the facility. This universal data exchange is especially useful for automated manufacturing facilities that employ cloud monitoring and control services, as well as for local data historians, which are used to monitor most continuous flow process systems, like oil refineries and beverage manufacturing. Historians record temperatures, pressures and other process set points so operators can check quality control measures by date, identifying, for example, whether there was too much water versus concentrate added to the beverage manufacturing process one day.
In the controls world, there are two main types of control systems: continuous flow processes like oil and chemical refineries that always have materials flowing into and out of huge mixing tanks and part A to part B digital processes like injection molding facilities equipped with lots of robots. SIMOCODE works perfectly in both because it’s ideally suited for monitoring voltage and current — or more — in any application with a motor or process.
What makes Siemens’ approach to motor management and controlsystems unique compared to competing solutions?
SIMOCODE is part of Siemens’ SIRIUS line of industrial controls and monitoring solutions, and its name is an acronym. The “SI” stands for Siemens, the “MO” stands for motor, the “CO” stands for control and the “DE” stands for device because it’s a Siemens motor control device.
Here at Siemens, we look beyond the motor and consider the entire process a motor is a part of when developing motor control and motor management solutions, because whatever the motor shaft is turning is equally important to the process. SIMOCODE solutions give customers the ability to monitor everything that affects the process the motor is part of. Other motor control manufacturers only look at the motor and don’t design with anything further than the motor shaft in mind.
For instance, I can expand SIMOCODE motor control capabilities by adding a temperature card that allows me to monitor the temperature of the gearbox the motor is turning. If the temperature started to rise, which could be caused by low lubrication oil, the SIMOCODE could stop the motor to prevent damage to the gearbox or the motor process. Or if I have a pump housing and the motor is staring to cavitate, or a bearing is starting to fail, a SIMOCODE equipped with a temperature card could monitor the temperature of the pump housing to stop the motor from running or prevent the operator from turning it on, which could accidently damage a very expensive motor or cause parts to break off into the medium that’s being pumped — like water or oil — and contaminate a large volume of product.
SIMOCODE can even be programmed to know which resistance temperature detectors (RTDs) in a system are monitoring which devices and use that data to not only identify that X gearbox is overheating but to communicate that X gearbox is overheating with a sentence like “RTD #1 over temperature.” Alternative motor control and management equipment typically communicates using hexadecimal codes that have to be deciphered to identify the issue. So, the SIMOCODE’s clear and precise alarms are a real separation, as its ability to identify issues with process equipment beyond the motor.
SIMOCODE can also be equipped with a vibration sensor designed to detect a 4–20mA signal from an accelerometer, identify misalignments, stop the motor shaft and whatever it’s connected to from causing damage that could result from a misalignment before it even happens and communicate why it’s stopping the process via text and alarms conveyed through the HMI.
In addition, SIMOCODE is modular and built for customization. The standard unit has four digital inputs and three digital outputs that can be used to stop and start motors and bring in stop/start control circuitry. Both versions of the SIMOCODE, the SIMOCODE pro S and SIMOCODE pro V PN GP (General Purpose), allow users to add modules for additional inputs and outputs and monitoring capabilities and are compatible with PROFINET. But the SIMOCODE pro S is compatible with all four main industrial communications protocols, Ethernet/IP, PROFINET, PROFIBUS and Modbus RTU, which — unlike most competing motor control and motor management solutions — enables near-universal communication with supervisory control systems. The SIMOCODE pro S can also accept a maximum of two digital modules, two analog modules, two RTD modules and one earth fault module, while the SIMOCODE pro V PN GP, which only provides current monitoring rather than current and voltage monitoring like the SIMOCODE pro, can accept just one of these cards. However, that tends to be plenty for the simpler systems these more cost-effective solutions are designed for. More complex systems should specify the SIMOCODE pro and add modules as their system demands.
Given its current and voltage monitoring capabilities, its advanced internal logic, its user-friendly HMI and the number of modules its compatible with, the SIMOCODE pro can even be used for machine safety. For example, I had a mid-sized hydraulic power customer who needed to achieve the machine safety level required for the hydraulic power units but didn’t want to invest in a safety PLC for the entire process because it was too much money for the capabilities required. So, instead, they equipped the system with a SIMOCODE pro and a Siemens safety relay, which offered additional ease of installation, enhanced interoperability and even some cost savings compared to a competing safety relay, and used the SIMOCODE’s custom configuration and motor management capabilities to achieve the motor safety level required for the process more affordably.
Another major difference between the SIMOCODE and competing motor control and motor management solutions is its ability to handle both resistive and inductive modes using the same hardware and software. Few to no competing solutions offer that capability without the addition of another product or different software, and it’s critical for heat tracing in applications like oil refineries. Heat tracing is used to help keep pipes from freezing in cold environments.
A process system with an inductive-only motor control and motor management solution can turn the heating elements on when it’s cold and off when it’s warm, but, unlike the SIMOCODE pro, they can’t monitor how much current the heat trace is using and identify when those components are going bad before they do. So, operators monitoring a process with a heat trace system and an inductive-only motor control and management solution would have to notice interruptions in or difference pacing for the pipe flow or wait for an alarm to learn that the heat trace system has gone bad, and because they didn’t know it was going bad in advance, may not have the parts on-hand to fix it before causing significant process disruptions and downtime.
Do you have any final thoughts or advice to share about motor management and control?
When you’re thinking about even simple motor management systems, think beyond the solid-state overload and voltage protection. Look beyond simple start/stop, overload, and HOA capabilities and think about how you can protect the entire process that the motor is interacting with. In some cases, you may need to add a timer or phase loss monitoring to protect the whole process, or you might need an energy meter to identify how many kilowatts per hour the motor is using. The SIMOCODE already offers these capabilities, so instead of adding additional hardware and software to the system — and the additional cost and potential points of failure that come with them — you’d just have to enable the action using the system logic and user-friendly HMI. SIMOCODE is extremely flexible. It provides operators with all the capabilities of a controls engineer, giving them full reign regarding how to monitor, protect, and react to any type of scenario that the motor may encounter and reliably protect both the motor and the process it’s a part of.
I once had a customer whose motor was very far away from his maintenance shop. A current monitor confirmed that current continued to flow into one of the two legs in the motor circuit even when the operator turned it off, preventing it from ever being fully off and significantly increasing the risk the motor contactor would weld shut, burn up the motor and render it useless. But instead of pursuing a preventative maintenance solution he hired a technician to come walk out to the motor and turn it off manually and, by the time he hired someone and that person showed up to complete the job, the motor had already burned up, costing the customer $200,000 plus 28 weeks of downtime to accommodate the motor’s lead-time. I was called out to help him protect the massive investment into his new motor, and I showed him that the SIMOCODE could detect the flowing current in the motor’s off-state and leverage its command feedback capabilities to turn off the circuit breaker that powers the motor via shunt strip. He bought and installed the SIMOCODE and, although it was more expensive than the solid-state overload relay he’d previously been using, its motor control and management capabilities provide robust protection for both his motor and process and will reliably save him from having to shell out $200,000 and tough out a 28-week production delay due to a burned-out motor.
SIMOCODE can also be retrofitted in any motor control center (MCC) to upgrade its control and data capabilities. I once had a customer that needed to get more data from his MCC but could not outright rip and replace it to achieve the new data and control options. I showed them how the SIMOCODE can be retrofitted into an existing MCC to expand data collection capabilities while keeping costs to a minimum, and they were very happy to improve the data and control capabilities of their existing structure and starters by installing the SIMOCODE. In the pictures below, you can see one motor control bucket updated with the SIMOCODE, as well as its placement and amount of room it took up inside the bucket.
Additional Information
Siemens has more than 50 years’ of proven experience designing, manufacturing and supporting the installation and maintenance of motor control and motor management systems optimized for the constant-speed, low-voltage motors used in virtually every application with a turning medium in the industrial, utilities and mining industries. For more information about the Siemens safety solutions available through RS Electronics, please visit the following links. For assistance identifying and deploying motor management and control solutions optimized for your unique application, please contact RS’s technical support team.
- Siemens’ Landing Page | RSElec.com
- Siemens’ SIMOCODE pro motor management and control devices
- Siemens’ SIMOCODE Pro products
- “How to use OPC UA With SIMOCODE pro in TIA Portal” video
- Siemens’ Industrial Controls – SIRIUS
- Siemens’ SIRIUS industrial control products
- Siemens’ SIRIUS Monitor solutions
- Siemens’ SIRIUS Modular System Flexible Assembly Options video
