Hello, I need some clarification on replacing my SLC 500 1746-NO4I analog output card. I have confirmed that the card outputs a 0-20mA signal by measuring it. I bought some used replacement cards, but discovered that the old card specifies an output range of -10vdc to +10vdc. I thought a voltage output card would be labeled NO4V. Unfortunately, I am unable to attach a picture at the moment. Can anyone help me understand this discrepancy?
Yes, you are right that the "I" in NO4I stands for current, as in the formula V=IxR. However, it's important to be cautious when purchasing secondhand cards as there are many counterfeits in the market. I recently had a negative experience when buying a secondhand safety input labeled as version 2.1, only to discover it was actually version 1.8 and therefore did not function properly. Make sure to verify the authenticity of products before making a purchase to avoid such issues.
JaxGTO pointed out that the "I" in NO4I stands for current (as in V=IxR), meaning that's its only function. It's crucial to be cautious when purchasing second-hand cards, as there are many counterfeits in circulation. I learned this the hard way when I bought a safety input labeled as version 2.1, which turned out to be version 1.8 and was incompatible. I believe one must make do with what is available when dealing with legacy equipment, especially with local pickups. It was confusing to see that replacement cards have the correct information, NO4I with 0-21mA, on the label. How significant are the version and revision numbers? The old card is simply labeled as SER A with no revision and was manufactured in 04/01 (23 years old). Contrastingly, the new cards are labeled as SER A REV A, MFG 03/08, and SER A REV B, MFG 04/10.
Greetings to all those who come across this post. I finally decided to take a chance and swapped out my potentially defective card with a second-hand REV A card. The machine is now functioning smoothly. I did need to adjust the analog outputs to a lower speed, as they were too fast with the new card. This serves as further evidence that the old card was indeed failing and not operating at its optimal level. Thank you for the assistance.
It sounds like you're running into a common mix-up with the SLC 500 series. The 1746-NO4I is indeed an analog output card that can be set for 0-20mA outputs, which seems to align with your measurements. However, it also supports a voltage output capability that can be configured to output a -10V to +10V range, which might explain the discrepancy you noticed. It's easy to confuse these two modes, especially if the configuration has changed over time in your application. I’d recommend checking the configuration settings in your PLC program to see how the card is set up, as well as confirming that the replacement cards you bought are also the same model and can operate under the same conditions.
It sounds like you're dealing with a bit of confusion around the card types! The 1746-NO4I is indeed an analog output card meant for current output (0-20 mA), while the NO4V is specifically for voltage output (-10 V to +10 V). It’s possible that the original card was misidentified or mislabeled at some point in its life, which can happen often with used equipment. To avoid further issues, I’d recommend double-checking the documentation or specifications for the cards you purchased to ensure they match your application. If they're indeed NO4I cards, you should be good to go, but if they're NO4V, they'll give you that voltage output instead.
It sounds like you're dealing with a bit of confusion there! The 1746-NO4I card does indeed output a current signal, while the 1746-NO4V is meant for voltage outputs. It's possible that the earlier configuration you measured was set up in a way that made it effectively output in the 0-20mA range for a specific application, hence the misunderstanding. Check the documentation for both cards to ensure they match your requirements, and if possible, confirm that your system is expecting the output type you're trying to replace. If you're aiming to switch to a voltage output, you'll definitely want to stick with the NO4V card for compatibility.
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Answer: Answer: The discrepancy in output range could be due to a mislabeling or a different card model being used. It's important to verify the card's specifications and compatibility with your system.
Answer: Answer: While the NO4V designation is commonly associated with voltage output cards in the SLC 500 series, there could be variations or alternative labeling schemes used. It's recommended to refer to the official documentation or contact the manufacturer for clarification.
Answer: Answer: To ensure compatibility, it's crucial to match the replacement card's specifications with the original card, including output range, signal type (current or voltage), and model number. Consulting with a professional or the manufacturer can help in selecting the right replacement card.
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