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CIN High Error

RichG 3 weeks ago in IQANdesign • updated yesterday at 10:22 p.m. • 2

I'm using a CIN input to monitor a 4-20 mA signal. I have the Calibration set to {4000; 15000; 0; 137.5} Per the manual, the Error Value should result at the 'Illegal Value' point. For a Low Error, this occurs at 2 mA as expected. I assumed the Max input value to be 20 mA, and my Max value is set to 15 mA. The halfway point between them is 17.5 mA. For some reason the High Error condition is not happening. Am I using the wrong signal max value of 20 mA? If so, what should that value be?

In contrast, the Low and High Error points for a VIN are working exactly as expected when using a Vin Max of 5 Vdc.

I've found this to be true for both IQANsimulate and the actual hardware.

I'm using an MC43FS and IQANdesign 7.06.22.11482.

Thomas Moberg (System support) 2 weeks ago

Hello.

You are not using the input wrong or misunderstand the instructions.

I did some testing here myself and set the max to 10 mA and got the high error at 21 mA.

Setting the max to 8 mA gave the the high error at 20 mA.

So the upper limit is seems not to be at 20 mA but at 32 mA.

Need to look in to this behavior more to see if it is a bug.

RichG yesterday at 10:22 p.m.

Any further developments regarding this issue?

I did some testing on my end with a MC43FS. I increased the current into a CIN input until a High Error triggered. This occurred around 24-25 mA. Once triggered the controller was locked in the High Error state. Reducing the current to the input did not clear the High Error. The only way to clear it was to restart the controller.

Image 5376

I see in the documentation that the Overcurrent Protection is "typ. 25 mA" so I suspect this is what is happening.

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