Understanding the Significance and Color Codes of Stack Lights in Industrial Machinery

Stack lights, also known as signal towers or smart lights, are commonly used in industrial settings to visually convey machinery or process status. These lights consist of a vertical stack of colored lights that are easily seen from a distance. The importance in industrial machinery lies in providing quick and clear visual indicators, improving workplace communication and safety.

Key functions advantages

Stack lights in industrial settings offer the following key advantages:

Status indication: Operators and workers often use stack lights to indicate the operational status of a machine or process. See below the different colors representing different conditions, allowing for quick assessments of situations. Operators and workers often use stack lights to indicate the operational status of a machine or process.

Warning and alert signals: Stack lights can be configured to emit specific colors, warning of potential issues or alerting personnel to take specific actions. For example, a flashing red light might indicate a critical fault or emergency.

Efficient communication: The use of colors in stack lights provides an efficient and intuitive means of communication. Even in noisy or busy industrial environments, workers can easily understand the status or conditions indicated by the lights.

Increased safety: By providing immediate visual feedback, stack lights contribute to a safer working environment. Operators can respond promptly to changes in machine status or emergency situations, reducing the risk of accidents.

Customization: You can customize stack lights to suit specific applications by configuring the sequence of colors, determining the meaning of each color, and designing the overall layout to match the needs of the facility.

Decoding stack light color codes

Specific color codes can vary between industries and applications, so it is essential to refer to the documentation provided by the equipment manufacturer or follow industry standards for consistent use. The following are some common color codes:

Green typically indicates that the machine or process is in normal operation or that a specific condition is met.

Yellow/amber is often a warning signal, indicating a cautionary state or a need for attention without immediate danger.

Red indicates a critical or emergency condition requiring immediate attention. It can signal a fault, shutdown, or other urgent issues.

Blue sometimes displays a maintenance or service in progress. It can also represent a specific machine status depending on the system configuration.

White conveys a particular status, such as a change in production mode, or it can have a custom meaning based on the application.

In summary, stack lights are essential in conveying machinery or process status in industrial settings. Their advantages include efficient communication, warning signals, increased safety, and customization for specific applications through color codes.

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Boost Size-Change Efficiency with IO-Link Magnetic Encoders and Visualization

In many industries, especially in Packaging, the need to minimize capital equipment costs drives engineers to implement low-cost, manual methods of size change (also called format change) on their machinery. In most cases, this means hand-driven cranks with mechanical dial pointers and/or mechanical revolution counters.

While cost is saved on the procurement side, cost is also shifted over to the operational side. Plant management is left with the task of keeping accurate records of various machine set-ups needed to run different products, as well as the task of training machine operators to perform all machine set-ups correctly. It doesn’t always go as smoothly as expected, and machine reformatting can result in longer downtime than planned, machine stoppages, and possibly excessive scrap.

The key to size-change improvement is capturing the linear movements of the machine components and bringing them into the control system, and then providing “smart” visual feedback to the machine operator during setup. For capturing machine position, a robust and cost-effective magnetic linear encoder is ideal. However, traditional linear encoders deliver an A-B quadrature incremental signal, which requires re-homing upon start-up or after a power loss. What’s needed is an absolute encoder signal, but that brings other challenges such as the cost and complexity of implementing an absolute signal like SSI (Synchronous Serial Interface).

Fortunately, there’s a new encoder interface BML SL1 Absolute Magnetic Encoder with IO-Linkoption that eliminates the problem of non-absolute feedback and the hassle of absolute position signal interface: IO-Link. IO-Link is a multi-vendor, non-proprietary, device-level serial digital interface that can be aggregated onto today’s Ethernet industrial networks. Magnetic linear encoders are now available that feature absolute position indication combined with the ease and convenience of the IO-Link communication protocol.

Now we just need to provide visual feedback to the machine operator regarding which direction and how far to turn the hand cranks. Once smartlight_18x18_300dpiagain, IO-Link provides the answer in the form of an IO-Link-enabled, fully programmable multi-segment LED stack light. When a new machine set up is required, the position parameters are stored in the controller. The controller communicates over IO-Link to the LED stack lights, indicating to the operator which dials need to be turned and in which direction. For example, a horizontally mounted stack light could be lit red on the right half, indicating that the dial needs to be turned to the right. As the position moves closer to the proper setting, the red segments count down until the entire stack light goes green, indicating that the correct position for that axis has been reached. No paper records to maintain and store, and very little training required with the intuitive operator visualization.

For more information about IO-Link linear encoders click here, and to learn more about IO-Link programmable LED stack lights visit www.balluff.com.

4 (More) Smart Applications for Process Visualization

In a previous post, 3 Smart Applications for Process Visualization, we discussed how the term “process visualization” has evolved since the introduction of the SmartLight. While it can definitely be used as a stack light, its additional modes can be applied for all sorts of different operation/ process visualization tasks. Below are a few more examples we’ve come across.

Use Case #4:  Fill Level Status:

From micro-breweries to steel-mills and oil refineries, all have state-of-the art tack fill level detection systems measuring fill levels to the last millimeter or in some cases cubic inches. But when you want to take peek at the how much the reservoir is full at any given time- you have to go to the HMI in some corner to see that value. Nine times out of ten this fill indication provides you only with numerical value. What if SmartLight shows you the value visually using the level mode of operation? Then the decision to run another batch of bottle filling can be taken without going to that corner and punching some numbers. Additionally, the colors of the segments can be changed to indicate the temperature or pressure inside the tank or just different fill levels so the line supervisors can take decisions promptly on the next action.

Use Case #5: Interactive Operator Status:

Several times plants invest in huge TV monitors to provide a real-time visual feedback to their employees on how their operations are progressing compared to the quota assigned. At one plant, they found no increase in employee productivity with such investment because the TV monitors failed to provide a visual feedback. The television sets indicated 112/300 – which meant nothing to the operators. The SmartLight, however, provided them the feedback using the level mode of operation on how they are performing to the quota. The moment SmartLight turns yellow was an indication to the operator(s) that they are falling behind the level of the lighted LED indicated that they are closing the gap to their daily quota. If the operator notices problems with the batch of components or machine itself they could change the SmartLight to a run light mode with a push of a button indicating trouble in the workcell – the supervisor then can deploy the right maintenance person to the cell. Utilizing the SmartLight light not only provided instantaneous feedback on performance but also added efficiency in handling production issues.

Use Case #6: Improving Hazard Awareness:

In one automotive plant, the maintenance team designed an innovative solution with SmartLights for hazard communication. This plant has several automated guided vehicles (AGVs). The light indicators on these AGVs are the same type that was on the mast of most of the workcells in the plant. It was hard to notice when the AGVs were pulling out of and entering their parking stand. Maintenance engineers installed SmartLights on the mast of the AGV parking stand and with different color scheme and level mode indicated if the AGV is coming to stop or just starting the motion. This simple idea avoided daily occurrences of mishaps for the forklift drivers and operators.

Use Case #7: Identify Bottlenecks:

With linear assembly process it can be difficult to detect bottlenecks in the production process. With increase complexity of today’s production flows the bottlenecks dynamically change under various conditions. Installing SmartLights programmed to change their mode of operation depending on certain conditions (on-demand change of mode) could help point out bottlenecks in the current environment. For example, these days the automation controllers are equipped to calculate its overall equipment effectiveness (OEE). That information can be directed to the SmartLight. A specified segment may turn green when OEE >80%, turns yellow when 60% < OEE < 80% and red if the OEE falls below 60%.  Now, the plant supervisors can see the overall picture of the entire floor to make informed and timely decisions.

Use Case #8: Time Lapse Counter:

Wouldn’t it be nice to know how long it takes to replenish the stack of pallets in the robotic palletizing cell? Or how often the operator has to go into the cell (causing stop operations) for mis-fired sensor or dropped package? How about break-times for the operators? Well SmartLights can be used for all these types of operations. This can be done by changing the blinking frequency of the SmartLight segment, and changing the colors or modes of operations, a multitude of information can be displayed for various purposes.

We want to hear from you! Do you have a unique application for the SmartLight? Share your story with us here.

You can also learn more by visiting our website at www.balluff.us.

3 Smart Applications for Process Visualization

Stack lights used in today’s industrial automation haven’t changed their form or purpose for ages: to visually show the state (not status) of the work-cell. Since the introduction of SmartLight, I have seen customers give new meaning to the term “process visualization”. Almost every month I hear about yet another innovative use of the SmartLight. I thought capturing a few of the use-cases of the SmartLight here may help others to enhance their processes – hopefully in most cost effective manner.

smartlightmodesThe SmartLight may appear just like another stack-light.  The neat thing about it is that it is an IO-Link device and uses simply 3-wire smart communication on the same prox cable that is used for sensors in the field. Being an IO-Link device it can be programmed through the PLC or the controller for change of operation modes on demand, or change of colors, intensity, and beeping sounds as needed. What that means is it can definitely be used as a stack light but has additional modes that can be applied for all sorts of different operation/ process visualization tasks.

Use Case #1: Stack Light Mode for Operation Status – The number of segments can be programmatically changed from 1 to the max segment number provided by the light (up to 5 in a five-segment SmartLight). Colors can be changed to red, blue, green, orange, yellow, white, or any other color of choice. This is the most traditional application of the SmartLight.

Use Case #2: Format Change Indicator – Many of our customers use the level mode to provide feedback to the operators when they are making adjustments to the machine. For example: red might indicate that the machine is out of alignment, yellow might mean the machine is getting closer to the specified alignment, and green might mean the machine is in the zone of alignment. Using the SmartLight in this fashion helped our customers save time in product changeovers because the operators didn’t have to come out of the cell to view the alignment status on a small HMI.  When the alignment of the machine is complete, the SmartLight can be programmed to switch back to the status indication mode or whatever mode of operation desired.

smartlightgifcroppedUse Case #3: Run Light Mode for Maintenance Indication – In this mode there are two colors – one color for the background and another color for the running segment. Along the assembly line where there are multiple work cells continuously processing raw materials in lock-step operation, downtimes are extremely costly. The standard status indicator will only indicate a problem at the work cell when the system stops, but it will not indicate a lack of raw material, for example. The moment the stack light turns red, the operator or the maintenance person is rushed to the site to first figure out what’s wrong before solving the problem. In Run Light mode, the SmartLight can be programmed to indicate different colors for the running segment and the background to show that attention is required at the cell. For example, as long as the running segment is running the machine is operational, but the background color can be changed to indicate raw material shortage, the need for mechanical adjustment of the machine, or the need for some electrical maintenance. Using a SmartLight, whoever is rushing the cell has a very good idea of what is required of them to get the system back up and running.

There are several more applications we want to share. Before we do that, we want to hear from you! Do you have a unique application for the SmartLight? Share your story with us here.

You can also learn more by visiting our website at www.balluff.us.

A Simple Way to Improve Speed and Efficiency

We are all efficiency-hungry. We want everything from service in restaurants to production on our plant done efficiently. Sometimes we use the term “speed” interchangeably with efficiency. Is that really a big deal? Of course it is.  How many times have you placed an order at the drive-through window of a fast-food chain and gotten wrong items or incomplete orders? Why do they make mistakes? Because, they are measured on customer response time (speed) and not on accuracy of the delivery (efficiency) — again speed replaced efficiency.

So is the maintenance team at your production plant efficient or speedy?  In my opinion, once you have the right maintenance person for the problem at hand they would be both efficient and speedy. The point I want to make is that identifying what type of maintenance service your system needs is the important part in making your maintenance team efficient in responding. Another way would be hiring all-rounder maintenance person who can handle electrical, mechanical and all other issues that your system can throw at him/her. How many of those all-rounders you can find and keep?

Today, in most plants we see three-segment or five-segment stack lights on almost all sorts of equipment that tells you the status of the work-cell: Green = everything good; Red = Need maintenance now!!! But, does it tell you about type of maintenance? So, what do we do? We send our maintenance tech out to the system; he looks up error codes on the small 8×10 HMI and figures out that the system needs an electrical tech to handle the situation. Wouldn’t it be nice, if that stack-light was a little smarter to tell you that “Hey, this system needs {electrical, pneumatic or mechanical} maintenance” instead of just flashing a red light? If it was that intelligent it would probably also tell you that this work-cell is running out of raw materials, or how the system is performing to the production quota etc.

SmartLightWell, I have great news: since the introduction of our one of a kind SmartLights our customers shared so many novel uses of this intelligent LED tower light that it is hard to capture all of them in one blog. I would like to share some quick examples though. As this SmartLight has three programmable modes of operations; stack-light mode, run-light mode and level mode, there are several possibilities of showing different information about the system using the single SmartLight. In one application, when the system needs operator/maintenance intervention, the controller (PLC or computer) switches the SmartLight in run-light mode and utilizes different combinations of foreground and background colors to indicate what type of maintenance and what severity of maintenance is needed. In another application, our customer utilizes the level mode of operation to show how different stations are performing so that plant supervisor and pin-point the bottleneck of the process and provide needed support to ensure efficient operations in the plant. Furthermore, lots of these applications were done as an after-thought to the existing systems in place.

SmartLight is one of the ways to improve your efficiency and speed. If you have unique SmartLight application to share feel free to comment on this blog.

Learn more about the SmartLight in our video library or on our website at www.balluff.us/smartlight.