Building a PLC-Controlled Music Player: Tips and Challenges

Are you anticipating the Programmable Logic Controller to produce the necessary sounds?

• 08-09-2024
• parky

parky expressed concern about a 120v AC to 24v DC 5 amp rectifier, hoping it functions as a power supply. This setup is being wired on a desk at home, where caution is exercised with anything above 120v. A past experience of being electrocuted by 270v serves as a reminder to prioritize safety when dealing with high voltage levels.

• 08-09-2024
• Glass_ST

Parky inquired, "Do you anticipate the PLC generating the sounds?" The PLC itself will not produce the sounds, but rather, it will communicate with another component that will.

• 09-09-2024
• Glass_ST

This project requires a specialized approach, as it involves playing audio files based on specific conditions. Typically, PLCs are not used for this purpose unless it is for a unique application, such as assisting visually impaired operators on assembly lines. To achieve this, a PLC capable of Modbus RTU communication, like a micrologix 1100/1400, is necessary. For those seeking a Modbus RTU MP3 player, platforms like Aliexpress offer suitable options, like a generic MP3 player with RS485 capabilities. Additionally, options like the Sparkfun MP3 Player, which supports up to 255 tracks, or Halloween prop controllers that can be triggered externally, are worth exploring. Overall, this is an unconventional industrial application, requiring skills in Modbus, Serial, or Binary output control alongside knowledge of MP3 device integration.

• 09-09-2024
• arpus4KM

If you're looking to control a 1734-AENT remote IO module (Point I/O) with a PLC, it's important to know the number of inputs and outputs needed. Additionally, having the right software installed on your PC is crucial. While Studio5k is a popular option, it can be on the pricier side. Let's first identify your hardware requirements before diving into the programming process.

• 09-09-2024
• geniusintraining

In response to a query from geniusintraining about programming a 1734-AENT remote IO module with a PLC, the suggestion was made to focus on hardware requirements first. Determining the number of inputs and outputs needed, along with the software being used on a PC, such as Studio 5000, was advised. While Studio 5000 is a popular option, its cost may be a factor to consider. It was suggested that building a system from scratch, rather than relying on a pre-made trainer, would be beneficial. With a requirement for 8 inputs and 8 outputs, the question of whether the compact 5370 PLC controller would be suitable arose. The affordability of Studio 5000 was also discussed, prompting a query about cheaper alternatives that could be used for programming. While Studio 5000 is currently available at work, finding a cost-effective solution for home use was considered.

• 09-09-2024
• Glass_ST

arpus4KM mentioned that Aliexpress is a great platform for finding miscellaneous items, such as a generic MP3 player that utilizes RS485 technology. It seems like all you may need is a pre-packaged speaker. This setup appears to be ideal, especially when paired with outputs featuring a latch connected to positive triggers for optimal functionality. Check out Aliexpress for more items like this!

• 09-09-2024
• Glass_ST

If I were to create PLC trainers, I would opt for the 1769-L16ER-BB1B or L18 models from CompactLogix as they offer compatibility with Studio5k specifically designed for them, such as the PN 9324-RLD200ENE version. This option is not only more cost-effective, but also ensures seamless integration. You can find these components for around $1,000.

• 09-09-2024
• geniusintraining

When it comes to building PLC trainers, I recommend using the 1769-L16ER-BB1B or L18 models due to their compatibility with Studio 5000 software, specifically designed for CompactLogix PN 9324-RLD200ENE. This option can be more cost-effective, priced at around 1k. Is there a specific reason for choosing the 1769-L16ER over other models, or is it based on factors like cost and size? Can the CompactLogix PN 9324-RLD200ENE Studio 5000 variant work effectively with the 5380 series controllers like the 1769?

• 09-09-2024
• Glass_ST

The price of an L16 is more cost-effective than an L33 due to its built-in I/O. For your specific needs, a high memory or processor capacity is not required. The software version should be compatible regardless of your choice. However, please note that the software is a full version but is restricted to CompactLogix and not compatible with ControlLogix. It is advisable to verify this information to potentially save money.

• 09-09-2024
• geniusintraining

I recently delved into Studio 5000 at work and wanted to share my progress. Currently, I am facing a challenge in configuring a blocking bit to avoid simultaneous activation of multiple Play_signal bits. After some experimentation, I have devised a method that involves using MOV instructions to move a number to an EQU, creating a more streamlined system.

• 09-09-2024
• Glass_ST

I must admit, these push buttons are quite pricey. One approach is to combine all outputs onto a memory bit and use the NOT memory bit in each rung. This way, once an output is latched, no other output can be activated until the reset button is pressed. The first rung should also include an unlatch of the memory bit associated with the pressed button (M21 in this case). To ensure output latches are activated, incorporate a NOT contact in all rungs. It is not necessary to use NOT contacts for all other buttons unless there is concern about multiple buttons being pressed simultaneously within the PLC's scan time. There may be alternative methods to achieve this as well. Apologies for the technical jargon, but you get the gist of it.

• 09-09-2024
• parky

Glass_ST mentioned that after spending time working with Studio 5000 at work, they have made progress. Their current challenge is preventing multiple Play_signal bits from activating simultaneously. They have come up with a solution involving using a blocking bit. Another idea is to simplify by NOR-ing all Play_signal_OP_n bits to a single coil and using that coil's operand to energize each push button. In the case of both push buttons being pressed in the same scan cycle, Kernighan's algorithm can be used as a workaround for this private project. However, it may not be suitable for an industrial application.

• 09-09-2024
• drbitboy

I witnessed a deep dive into technical concepts that are beyond my usual experience. Can you simplify these topics in layman's terms for me?

• 09-09-2024
• Glass_ST

Parky remarked that the push buttons in the set were quite pricey. However, the investment is worth it for creating a unique and impressive project that sets me apart from my colleagues. I may even consider adding more features or upgrading it in the future. It's a refreshing change from the mundane task of simply operating an actuator.

• 09-09-2024
• Glass_ST

Want to explore new possibilities without additional hardware? With access to an HMI and a PLC processor (no I/O required), you can create innovative projects using simulation. By utilizing an HMI or simulator, you can design logic for processes like batching or robotics without the need for actual I/O. By simulating the process with a combination of HMI and PLC, you can animate and run the project smoothly. This method has been successfully used in various projects, with simulation software like Prosis or Pics. By simulating with around 2,000 I/O points, modifications can be made before visiting the site, saving time and ensuring a smooth commissioning process. By mapping real I/O to internal bits and utilizing simulation code in PLC blocks, you can debug and fine-tune the process efficiently. This approach minimizes the need for on-site modifications during commissioning.

• 09-09-2024
• parky

Glass_ST inquired about concepts that were unfamiliar to them and sought a simplified explanation in layman's terms. Can you elaborate on these unfamiliar bits for beginners? Which concepts are new to you?

• 09-09-2024
• drbitboy

DrBitBoy asked, "Which bits are unfamiliar to you?" Dive deeper into the concepts of NOR, NOT, and OR. Click here to learn more.

• 09-09-2024
• Glass_ST

When you mentioned bits, I initially thought you were referring to binary digits, which made me realize I may not be very bright. To further understand this concept, take a look at Boolean Logic. It is a formal concept that is likely familiar to you based on your code. In Boolean logic, there are three key operators: AND, OR, and NOT. AND is a binary operator that requires two operands to evaluate. In ladder logic, it is represented by placing two contacts in series on the same rung or branch. If both contacts are true, the output rung will be true. OR is another binary operator that is implemented in ladder logic by placing two contacts in parallel. If either contact, or both contacts, are true, the output rung will be true. NOT is a unary operator that operates on a single operand. In ladder logic, it is implemented using the -|/|- contact, also known as Normally Closed or NC. It can be argued that this, along with Normally Open or NO contacts, are essentially AND operators as they combine the true/false state of their input rung with the operand evaluation. All other operations in Boolean logic are built on these fundamental operators. For example, NOR is a combination of NOT and OR. DeMorgan's Laws state that "NOT (a OR b)" is equivalent to "(NOT a) AND (NOT b)." Therefore, NOR can be implemented as a series of NOT contacts. By understanding these fundamental concepts, you can effectively apply Boolean logic to your programming tasks.

• 09-09-2024
• drbitboy

After analyzing my work, it seems that I have created several NOT gates. There is probably a function in Studio that can achieve the same result, but the AND, OR, and NOT functions are typically used as outputs. How can I convert one of these functions into an input? While it may not significantly impact a program of this scale, it is valuable practice to comprehend these tools (developed by individuals with far greater expertise than my own) in order to enhance my performance in my role.

• 09-09-2024
• Glass_ST

Sometimes, taking a longer route can be more beneficial than creating a complex function. It all boils down to how others perceive your code when troubleshooting. For instance, the use of "NOT" bits can be likened to a relay system, where the coils act as relays and the contacts serve as interlocks derived from these relays. While it may be tempting to streamline the process by implementing indirect addressing in a loop to reduce the amount of code, it doesn't necessarily improve speed since it still has to iterate through the same information repeatedly. Consider a scenario where you have 10 variables representing outputs, each corresponding to a specific integer value in a register. Instead of creating 10 separate rungs with comparisons for each output, you can utilize indirect addressing to achieve the same result in just a couple of rungs. This approach makes it easier to handle multiple outputs based on the value stored in the variable without the need for extensive comparisons. As seen in the example, assigning a value of 2 to the variable activates output 2, while assigning 4 activates output 4, and so forth. While this method may seem daunting for beginners, mastering the capabilities of PLCs opens up various efficient programming techniques. Remember, there are always multiple ways to achieve the same outcome in PLC programming.

• 09-09-2024
• parky

Glass_ST asked how they could utilize a-( )-coil instruction to create an input. To achieve this, one must place the a-( )-coil instruction at the end of a rung, with that rung serving as the coil's input rung, and utilizing an internal memory bit as its operand. In the event that the rung state is True during the evaluation of the coil instruction, a value of 1 will be stored in the internal memory bit. Conversely, if the rung state is False during evaluation, a value of 0 will be stored in the internal memory bit. This internal memory bit can then be used as an operand in a single contact on subsequent rungs to retain the Boolean result, eliminating the need to recreate complex Boolean logic with multiple contacts in series and/or parallel. It is important to note that the user program can only read and write 1s and 0s to memory bits based on its logic. The memory in a PLC is categorized into three primary groups: input memory, output memory, and internal memory. The user program does not directly read physical inputs, but instead reads memory bits that mirror the states of the PLC's physical inputs. These memory bits are updated from the incoming electrical signals of the physical inputs by the PLC's operating system independently of the user program's execution. Similarly, the user program does not directly control physical outputs; it writes to memory bits representing the desired state of the physical outputs, which are then interpreted by the PLC operating system and converted into electrical signals for the physical outputs. Internal memory serves the purpose of allowing the user program to store Boolean calculations from one rung to the next, and even across scan cycles.

• 09-09-2024
• drbitboy

Glass_ST inquired about using a specific method to create an input. The key point to understand is that inputs and outputs are not physically created, as all instructions in a PLC simply read or manipulate memory. Whether it's an XIC (examine if closed) or XIO (examine if open) contact instruction, the focus is on the address of the memory bit and its value of 1 or 0. This applies to coils as well, which can even overwrite the value in an input memory bit. This can result in different interpretations by later contacts until the PLC system re-scans the physical input state and updates the memory bit accordingly.

• 09-09-2024
• drbitboy

I can feel my brain aching after that.

• 09-09-2024
• Glass_ST

Glass_ST commented that their brain was hurting after attempting to learn PLC programming. If you truly want to learn, then hands-on experience is key. Consider downloading RSLogix Micro Starter Lite and RSEmulate 500, which is a free tool. This software may not be exactly like logic 5000, but it will get you started without the need for a physical PLC. PLC programming revolves around timing, with the scan cycle acting as the clock. Check out this video series for more information. The Boolean aspect of programming is considered the more straightforward part of the process.

• 09-09-2024
• drbitboy