Greetings, Currently, we are in the process of a project involving the integration of a linear potentiometer with our Beckhoff PLC system. Through our research, we have identified the EL3255 EtherCAT Terminal as an ideal solution with 5-channel analog input specifically tailored for potentiometers ranging from 300 Ω to 50 kΩ, operating at 16 bits. Our strategy involves supplying either 10V or 24V to the potentiometer and then connecting the wiper back to the input. This method will enable us to effectively monitor the position of the potentiometer. However, we have encountered an obstacle concerning the potentiometer's maximum recommended wiper current, usually indicated as 1µA or 1mA (for up to 1 minute during an error). The EL3255 documentation specifies a maximum output current of "0.3 A total supply current for the potentiometers." Our inquiry revolves around the possibility of adjusting the output current through the Beckhoff settings. Alternatively, do you have any suggestions on how we can ensure that our current levels remain below the 1µA threshold as per the standard potentiometer specifications? We appreciate your support in advance. Best regards, Jasper
Analyzing the data of EL3255 reveals that the terminal outputs 10 VDC power for each potentiometer. The internal resistance for each wiper input is a minimum of 100 kOhm, with the largest potentiometer resistance that can be accommodated being 50 kOhm. This implies that the minimum detectable current is 7 µA (10 V / 150 kOhm). One microampere as the maximum potentiometer current seems insufficient in my opinion. Additionally, the maximum total supply of 10 V for all channels used is 0.3 A.
After reviewing the data for EL3255, it is evident that each potentiometer receives 10 VDC power at its terminal. The internal resistance for each wiper input is a minimum of 100 kOhm, with the maximum potentiometer resistance it can handle being 50 kOhm. This implies that the smallest detectable current is 7 µA (10 V / 150 kOhm). With a maximum potentiometer current of 2 µA, some may find this too low. The total 10 V supply for all channels should not exceed 0.3 A. It is worth noting that there is a potentiometer with a maximum current of 1 mA as an alternative. The EL3255 specifications indicate ">100kOhm", suggesting that the actual value may be higher to prevent potential issues with potentiometers.
Hi Jasper, Your plan for monitoring the position of the potentiometer with the EL3255 EtherCAT terminal seems quite solid. However, regarding your inquiry about adjusting the output current through the Beckhoff settings, I'm not entirely sure their system provides such customization features. What I do suggest is considering the use of a voltage divider or a current limiting resistor, which should help lower the current to your desired level. This is a more hardware-focused solution rather than adjusting settings in your PLC. I also recommend double-checking your system's requirements so you can choose the most appropriate hardware to match. I hope this helps and best of luck with your project!
Hi Jasper, It's always exciting to see practical applications of potentiometers, and it sounds like you've done some solid groundwork. Regarding your question about current adjustment, typically, the Beckhoff terminals do not provide an option to manually adjust the output current. However, this doesn't mean you are out of options. A common workaround is to use a high resistance value potentiometer that fits within the resistance range of the EL3255; this will naturally drive the current down. Alternatively, one could integrate a high resistance series resistor with the circuit to ensure that the wiper current stays well below 1µA. Always double-check the selected resistance value to ensure it will not affect the voltage range nor hinder your ability to accurately read the potentiometer's position. Furthermore, you could consider using a digital potentiometer with a built-in current limiting feature. However, you would need to ensure that it's compatible with your Beckhoff system. I hope this gives you a direction to proceed in, and I wish you the best of luck with your project! Cheers!
Hi Jasper, It's indeed crucial to ensure you're not exceeding the maximum recommended wiper current. As per my understanding, the 0.3 A that you mentioned from the EL3255 documentation refers to the total supply current for all five potentiometers. This means that it's the current available for all the connected potentiometers, and not the current that flows through one specific potentiometer's wiper. You may not be able to directly control the output current through the Beckhoff settings; however, since the EL3255 provides a constant voltage, you can indirectly control the wiper current. It will be proportional to the resistance of your potentiometer. So to keep the current below 1µA with a 24V supply, make sure your potentiometer resistance isn't less than 24M Ohms. Just be sure of your potentiometer's actual maximum resistance value, as actual values can sometimes be lower than nominal. Hope this helps, and best of luck with your project! Best, [Your Name]
Hi Jasper, Unfortunately, you can't adjust the output current through the Beckhoff settings. The Beckhoff terminals are designed to have a fixed output current which can't be altered. However, you can work around this issue. Perhaps you could implement a current-limiting circuit which uses a resistor or a current-limiting diode in order to keep your current levels within the required threshold. This process may involve going through some calculations to ensure you are not overloading your potentiometer, but it certainly provides necessary control over the current. Remember, safety and the adherence to specifications are paramount to preserving your circuit's integrity. All the best, [Your Name]
Hey Jasper, it sounds like you're on the right track with the EL3255! To stay under the wiper current limit, one option is to use a resistor in series with the potentiometer wiper to restrict the current flowing through it. Another approach is to check if there's a specific configuration in the Beckhoff software that allows you to fine-tune the output current settings, though I’d be surprised if they allow for such low values directly. Lastly, you could consider using an analog buffer circuit to manage the current effectively. Hope this helps, and best of luck with your integration!
✅ Work Order Management
✅ Asset Tracking
✅ Preventive Maintenance
✅ Inspection Report
We have received your information. We will share Schedule Demo details on your Mail Id.
Answer: Answer: The EL3255 EtherCAT Terminal is identified as an ideal solution with 5-channel analog input tailored for potentiometers ranging from 300 Ω to 50 kΩ, operating at 16 bits.
Answer: Answer: By supplying either 10V or 24V to the potentiometer and connecting the wiper back to the input, the position of the potentiometer can be effectively monitored.
Answer: Answer: The potentiometer's maximum recommended wiper current is typically indicated as 1µA or 1mA (for up to 1 minute during an error), while the EL3255 documentation specifies a maximum output current of "0.3 A total supply current for the potentiometers."
Answer: Answer: The possibility of adjusting the output current through Beckhoff settings or suggestions to ensure current levels remain below the 1µA threshold as per standard potentiometer specifications are topics of inquiry.
Join hundreds of satisfied customers who have transformed their maintenance processes.
Sign up today and start optimizing your workflow.