Hey everyone, I wanted to bring to your attention an issue that a colleague of mine recently encountered. The new 5380 Compact GuardLogix safety outputs (5069-OBV8S) come with a no load detection feature that cannot be disabled. Even Safe Torque Off (STO) is not sufficient as a load to prevent the outputs from faulting in the absence of a load. This means that you cannot connect these safety outputs directly to STO without having something else in parallel to serve as a load. Rockwell Automation's official solution is to use a 2.4k resistor. This issue likely extends to the 1756-OBV8S and the new Flex 5000 safety outputs, with the exception of the safety relay outputs. This oversight by Rockwell Automation is quite significant. Hopefully, a firmware update will be released soon to address this issue, but as of now, there is no concrete information available. For more detailed information, please refer to Rockwell Automation Technote 1091239.
It seems like this issue should have been easily identified during the module design phase. [Yes, I must admit it did sound amusing in my mind]
I also would have assumed the same thing on both fronts.
Interesting information! According to ASF, the official solution recommended by RA involves using a 2.4k resistor. It's clear that there was a significant oversight by RA in this matter. It is hoped that a firmware update will be released soon to address this issue, although details are currently scarce. Alternatively, it seems that RA may be encouraging customers to purchase their ERS2, ERS3, or PF527 models which come equipped with CIP Safety features, but come with a higher price tag. As pointed out by AustralIan, it seems like this issue should have been noticed during the module design process. Humorously enough, I agree with this sentiment.
In a recent conversation, Jeev suggested that some companies may push for purchasing their ERS2/ERS3/PF527 models with CIP Safety, despite their higher cost. However, he also hinted at the upcoming release of a Rockwell Cat 4, PLe, SIL3 Safety Rated 2.4k Resistor in early 2020, enticing potential buyers with advanced safety features at a competitive price.
ASF hinted at the release of a highly anticipated Rockwell Cat 4, PLe, SIL3 Safety Rated 2.4k Resistor set to debut in early 2020. But some are wary of the potential impact.
Thanks for bringing up this issue. Seems like a strange oversight on Rockwell Automation's part. I faced a similar issue, and I can testify that the 2.4k resistor workaround does its job, albeit grudgingly. It's not an ideal state of affairs, especially if you are working with multiple safety outputs, that can be both, time-consuming and less efficient. I hope they indeed release a firmware update, but in the meantime, everyone should be aware of this and plan their projects accordingly. Moreover, this issue underlines the importance of comprehensive testing and troubleshooting before implementing new technology on a wide scale.
Thanks for bringing this up, it really highlights a significant design oversight by Rockwell Automation. While the inclusion of a 2.4k resistor may solve the issue for the time being, it's far from a long-term solution. It's clear they need to come up with a more elegant solution to this problem, ideally with a firmware update that resolves the issue outright. At the very least, they should be providing more comprehensive information about the issue and their plans to address it - right now, it feels like we're left in the dark.
Wow, I didn't realize that there was an issue with the no load detection feature on the 5380 Compact GuardLogix safety outputs. Thanks for bringing this to the forefront! It's unfortunate that Rockwell didn't foresee this problem, as it puts an additional burden on the users. While using a 2.4k resistor seems like a decent workaround, a patch would definitely be more desirable. Hopefully, they'll be offering a firmware update for this soon. Will keep an eye on Technote 1091239 for any updates. Really appreciate your input on this.
Thanks for bringing this up! It’s definitely concerning to have those limitations with the 5380 Compact GuardLogix outputs, especially since safety systems are all about reliability. Using a resistor as a workaround seems a bit clunky, and it would be great if Rockwell could push out a firmware update soon. It’s important we find a more streamlined solution, as anyone using these outputs will want to ensure compliance without extra components complicating the design. I’ll check out Technote 1091239 for more details.
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Answer: The 5069-OBV8S safety outputs have a built-in no load detection feature to ensure safe operation, but this feature cannot be disabled.
Answer: To prevent the outputs from faulting in the absence of a load when using STO, you need to have something else in parallel to serve as a load. One recommended solution is to use a 2.4k resistor.
Answer: Yes, this issue likely extends to the 1756-OBV8S and the new Flex 5000 safety outputs, with the exception of the safety relay outputs.
Answer: As of now, there is no concrete information available regarding a firmware update to address the issue with the safety outputs. For more detailed information, you can refer to Rockwell Automation
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