To troubleshoot a reset issue, inspect contactors KC0 and KC1 as they may be causing the problem. Refer to the diagram showing a NC contact in series between safety relay Y1 and the reset button. Check if one of the contactors is not fully engaged. You can verify this by pressing the buttons to see if they respond accordingly.
When motor contactors are de-energized, it is important to ensure there is a short across Y1 & Y2 (normally closed contacts from contactors) and also across S12 & S11 (Emergency Stop button). Pressing the reset button should result in terminals S31 & 33 being shorted. However, without knowing the part number of the ESR relay, it can be challenging to determine the wiring configuration. It appears to be set to operate in a single channel mode. It is crucial to check for bad joints, as this is often the cause of issues rather than a different problem. Be cautious not to mix up terminal connections, as some terminals receive modulated signals for safety reasons. Attempting to link out channels can cause the relay to blow, as the channels are meant to be separate for safety measures.
What are "bad joints" in a machine? I'm still learning how to navigate this complex piece of equipment. An ESTOP failure is preventing us from proceeding with our work. Most of these components are 25 years old. Thank you for sharing your expertise as I strive to understand more about this machinery.
The internal relays on ESR relays can become large due to age and vibration, causing the soldered joints to crack over time. This is often indicated by a small, fine crack ring around the solder joint. While ESR relays may be obsolete, there are modern equivalents available. Additionally, some ESRs have solder or plug-type terminals that can be affected by hot temperatures, vibrations, or corrosion, leading to bad joints or corroded connectors.
Discover a comprehensive guide for ensuring the safety of your operations with a safety relay manual.
Oh no, I chose the incorrect option!
I appreciate the information. I may need to inspect each wire individually for signs of corrosion. Although the system functions perfectly for weeks at a time, it can suddenly fail and go into emergency stop mode the following day.
mechtec admitted to selecting the wrong component and is now seeking guidance on whether to simply replace the relay component. Unfortunately, the individual responsible for testing the component is not available.
Take a look at these protruding plastic pieces: When the contactor is activated, they should retract to be more flush. If they both appear fully extended, you will need to use an ohm-meter to test for continuity. Disconnect the purple wire from terminal 31NC of Kc0 and test for continuity between that terminal and the opposite terminal (most likely labeled 32NC). You should observe a low resistance reading. Repeat this process for Kc1. If both readings are low, the issue lies elsewhere, possibly with the Safety relay A1 or the reset pushbutton.
John Lee asked if he could simply swap out the faulty relay component, as the person assisting them was unable to test it. Finding a newer model could be a straightforward replacement solution. However, it is important to note that while contactors typically fail more frequently than safety relays, it may not necessarily be the issue at hand in this specific scenario.
The safety relay model in question was discontinued in 2008, but there should be a suitable replacement available. When the LEDs indicate that the emergency stop circuits are functioning properly but the safety relay remains inactive, it could be due to a lack of reset signal reaching the relay or a faulty internal NC contact. Typically, these components are wired in series with the reset signal to ensure proper operation.
Thank you for your assistance. I will borrow a multimeter to check the electrical readings. What should the ideal number be for a low reading? So far, I haven't observed the components seating properly, as the machine is currently experiencing a malfunction and is not operational.
Refer to the schematic on page 8 to troubleshoot the relay reset issue. A connection between S33 and Y2 is essential for the relay to function properly. Ensure you have a setup with NC contacts in series with the start switch. Additionally, there might be a NO contact on another device like a key switch that needs to be activated before resetting the relay. The problem could be caused by a dirty NC contact in the circuit.
Thank you. I will check again tomorrow when I return to the shop to resolve the issue with our machine being down.
To ensure optimal performance, it is important to check for voltage drop across monitoring contacts, especially those designated as normally closed (NC) when relays are off. If a significant drop is detected, this could be the cause of any issues. Additionally, inspect the condition of the wires for signs of age and dirt buildup. Clean up connections and remove any dust or dirt with a vacuum if necessary. Lift the wires off the safety relay and test continuity across all contacts using a multimeter. This simple maintenance routine can help troubleshoot any potential problems with the system.
- 18-01-2025
- PLCstarter1884
Can you please tell me the meanings of NC and NO?
"Understanding the concepts of normally closed and normally open is essential in electrical systems. When referring to components like limit switch contacts or relay contacts, 'normally' indicates the default state when un-actuated or de-energized, respectively."
I am grateful for your assistance. Hopefully, I can troubleshoot this emergency stop failure that has suddenly occurred after the machine was running smoothly for over 3 weeks. Thank you once again for your help.
When a product is discontinued, finding a suitable replacement is crucial. While a recommended substitute may be available, it's important to note that the terminals could vary, requiring a reassessment of safety considerations.
When troubleshooting electrical issues in your machinery, it's important to check for voltage drop across monitoring contacts that should be normally closed when relays are off. A significant drop in voltage could indicate the problem. Additionally, inspect the condition of your wires as old or dirty wires may contribute to malfunctions. Clean up connections and remove any dust or dirt present. Lift the wires off the safety relay to test continuity across all contacts.
If your machine is in failure mode due to an emergency stop, examine the KCO and KC1 components. Look for specific voltage drop numbers or indicators to pinpoint the issue. Is there a way to temporarily bypass the failure to release the emergency stop and get the machine back in operation?
If you're facing challenges with your project, consider hiring an experienced professional to assist you. Calculating the cost of downtime can help you understand the urgency of the situation. Bringing in outside help can lead to quicker and more cost-effective solutions.
Regrettably, the issue of the German machine being down has resulted in high costs. Despite having an electrical technician on site, the machine's unique wiring has made it difficult to troubleshoot. I have attempted to resolve the intermittent ESTOP failure issue myself, as the machine has previously functioned without issue. However, resetting the machine multiple times has been the only temporary solution. The machine operates on 24v, so I am looking to identify any potential issues with the contactor or voltage. Currently, the relays show a green light. What steps should I take to diagnose and resolve this issue with the machine?
John Lee expressed frustration over the costly downtime caused by a German machine's unique wiring issues. Despite having an electrician on site, the problem persists. A simple check of the reset circuit should only take a competent electrician 5 minutes to determine if it is working properly. The safety relay specifically looks for a signal change between S33 and Y2. By removing the wires on these terminals and testing with a jumper, the relay should reset. If it fails to reset with "input A" and "input B" activated, then the relay may be faulty. On the other hand, if it does reset, the issue could lie with contacts KC0, KC1, or SbH1.
I will have a discussion with him to progress further. To better understand the process of "jumping wires" and voltage checking, I need to dive deeper into studying it. How do we determine which contact is faulty? This will likely be his next query. Thank you for being patient and offering assistance.
Apologies for the directness, but the mentioned circuit is quite straightforward. It appears that your electrician may simply be avoiding the issue. To troubleshoot, if connecting S33 and Y2 does reset the safety relay, and the problem is narrowed down to a field device, reconnect the wires on the safety relay and place a jumper on Kc0. Press the reset button to test Kc0, then repeat the process with Kc1. If the issue persists even with the jumpers in place, try momentarily jumpering the reset pushbutton. If none of these steps resolve the problem, there may be a faulty wire between the components.
joseph_e2 expressed frustration with the simplicity of the circuit and suggested the electrician might not want to troubleshoot further. To isolate the issue with the safety relay, try jumpering S33 and Y2, then test Kc0 and Kc1 with a jumper and reset button. If the issue persists, try momentarily jumpering the reset pushbutton. If none of these steps work, there may be a fault in the wiring between components. Despite ongoing challenges, the need to keep the machine running drives the effort to troubleshoot and resolve issues. Thankful for progress made so far, the journey to resolve the problem continues.
If you're looking for the best spot to go jumping at Kco or kc1, where should you take the leap?
Joseph_e2 mentioned that the circuit in question is straightforward, and suggested that the electrician may not want to address the issue. To troubleshoot, try resetting the safety relay by connecting S33 and Y2, then testing Kc0 and Kc1 with a jumper and reset button. If the problem persists, check for a potential wire issue between components. Another individual assisted in removing the jumper on the safety relay, confirming its functionality.
John Lee mentioned that the jumper on the safety relay was removed. Did you mean that a jumper was added across those two safety relay terminals? When it comes to the contactors, refer to this particular section of the diagram: Look for terminals 31 and 32. Connect a jumper from Kc1 terminal 31 to Kc1 terminal 32 and press the button. If it resets, then the issue lies with Kc1. If not, move the jumper to connect Kc0 terminal 31 to Kc0 terminal 32 and try again. If it resets, then Kc0 is the problem. If not, locate pushbutton SbH1 and briefly jumper its terminals 13 and 14. If it resets, then the problem is with the button. If none of these jumpers result in a reset, begin jumpering out wire segments. If the pushbutton is on a swiveling pendant, that would be the first point of suspicion for a wire problem. Run a new wire from Kc0 terminal 32 to SbH1 terminal 14 (keep it outside for now) and attempt to reset. If it works, replace that specific conductor. From my experience with German machines, it is likely within a multi-conductor cable. If one conductor is failing, the others are likely to follow suit, so it is advisable to replace the entire cable.
It was a relief to finally achieve success and overcome the obstacles without assistance. My assistant efficiently followed my instructions, resulting in the successful resetting and clearing of the ESTOP block with the s33 and y2 operations. The contacts were energized, and the machine was up and running smoothly again. However, we still need to identify and fix the problematic K component. Your response to my question is greatly appreciated.
I am unable to locate the pushbutton labeled SbH1 as shown in the diagram. I can see numbers 13 and 14, but SbH1 is not visible. Where can I find the SbH1 pushbutton as depicted in the diagram?
John Lee inquired about the ideal voltage drop number to look for while troubleshooting a machine in failure mode due to an ESTOP issue. He is currently testing the KCO and KC1 components and seeking guidance on what numbers to observe. Additionally, he is wondering if there is a way to temporarily bypass the failure. It is suggested to replace the Craftsman meter with a Fluke or Amprobe for more accurate readings. An unusual voltage drop in one contact may indicate a faulty component.
One suggestion is to disconnect the safety relay wires and manually wire in circuits to known good components to test for issues. If the machine still fails to reset, it may be a problem with the safety relay. It is advised to consider hiring a qualified technician to minimize prolonged downtime, as the cost is likely lower than losing significant machine run time. Feel free to ask for further assistance.
- 18-01-2025
- PLCstarter1884
If you're looking to reset the emergency stop on a machine, look for a button labeled "reset" or "power on." It may also be labeled in German as "NOT-AUS Quitt." Usually, to reset the e-stop, you just need to press the button. Is that not working for you?
When troubleshooting industrial equipment, it is essential to locate the "reset" or "power on" button. In this case, the button is labeled "NOT-AUS Quitt" in German, positioned above SbH1 on the page. Typically, pressing this button should reset the emergency stop (e-stop) function. However, if the button does not work, alternative solutions may be required, such as using a relay jump. Further testing may be needed to determine if a faulty K contact is causing the issue. Tomorrow, a more thorough examination involving contacts 13 and 14 will be conducted to address the problem effectively.
If you encounter problems with your safety relay after closing S11 and S12, try power cycling it. With 2-channel safety relays, the relay times the closure of the 2 channels. If the channels are not closed within a short time (10ms), the relay may not reset with the reset input and requires power cycling. It seems like the machine may have been imported, so it's important to review the safety systems thoroughly. European and Asian standards may differ from US standards, so it's crucial to ensure compliance to avoid fines and accidents. Many cases of non-compliance have been overlooked in the past, leading to safety risks. It appears that the safety relay wiring is not up to standard and should be redone to meet safety requirements.
Joseph_e2 noted that finding a newer model may be a simple drop-in solution. It is important to note that contactors often fail more frequently than safety relays. I recently performed a safety relay jump mentioned last week, and running it released the ESTOP failure on the Kc contacts. Out of the 4 total contacts, only one is moving in and out, while the others remain in place indicating they are energized. The machine is up and running, allowing us to fulfill orders. I aim to further understand how to explain the need to replace the other contacts to my manager. Your assistance is greatly appreciated.
I am uncertain about where Kc900 fits into the safety relay circuit. The wires you are following are purple and connect to terminals 31 and 32 of Kc0 and Kc1. If connecting S33 to Y1 of the safety relay resets it and allows the machine to operate, the issue may lie with Kc0, Kc1, or button SbH1. This also indicates a potential issue with the wiring. It is important to note that bypassing the safety relay's diagnostic check can compromise the safety devices. By bypassing this check, you may be putting people at risk as a failure in Kc0 or Kc1 could go undetected. It is crucial to address this issue before it leads to a dangerous situation. If possible, take a clear picture of Kc0 and Kc1 terminals for better guidance on troubleshooting. At this point, it is advisable to seek help from a professional who can assess the situation in person.
Once we fulfill this order, I plan to conduct tests on the Kco and kc1 as previously suggested. This testing will help us identify any potential faults and ensure that we are meeting our requirements.