1769-IF8 module doesn't read my analog input


I just noticed that your arrow highlights the differential voltage input. I presume you mean the next sample circuit below that, the differential current input. The comment above applies in any case.

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If your application absolutely cannot connect the DC common of the transmitter to the ANLG common of the IF8 module, you will need to use the 1769-IF4I module instead.



From Library of Congress Catalog Card Number 41-3345, 37th edition, Copyright 1960 (colon not emoji)
Chapter 2 Electrical Laws and Circuits Page 39 Impedance Matching Many Devices require a specific value of load resistance (or Impedance ) for optimal operation. The impedance of the actual load that is to dissipate the power may differ widely from this value, so a transformer is used to change the actual load into an impedance of the desired value. This is called impedance matching…However, there is another meaning. It is possible to show that any source of power will deliver it(’)s maximum possible output when the impedance of the load is equal to the internal impedance of the source. The impedance of the source is said to be “matched” under this condition. The efficiency is only 50 per cent in such a case; just as much power is used up in the source as is delivered to the load. Because of the poor efficiency, this type of matching is limited to cases where only a small amount of power is available and heating from power loss in the source is not important. (Copyrighted material cited here in part to satisfy query “Have you any documents…” yet partial citation of book name noted). Yes, I do.



pssssst! Dude! You’re beating a dead horse!



My educated guess is that the problem was solved in post #3 by the information supplied ( yet not taken C/O Mr. Bernie Carlton ) or your post, Mr.Turmel re: Highlighted info about within +/- 10 VDC of analog common. Since we have not heard from him since, I am pretty certain that the problem could have been resolved in post 3- yet he would not believe it until he saw your post #18 or #19. I am seldom offended by an honest question, and can usually prove that there is basis for what I say. There is often a gap between Too Much Information (TMI ) and insufficient information, of that I am certain.

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Hi jlivingston, Recently we had found the actual problem. the problem is not for connection & configuration etc…Generally when given 4mA to AI module across the I in+ & V/I in- terminal, it drops 1V (as per ohm’s law) reason for have a 250 ohm resistor across that terminal. same operation for when given 20mA it drop 5V. So AI module start to consider only when voltage drop across resistor is 1V, even it may be 4-20mA signal. But we had only 0.55V voltage drop across the 250 resistor. Hence we are focusing to improve our signal quality.

Thanks to all for Spending your valuable time to give the comments.

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Mr.pturmel, I think you have a bragging attitude. I found that since your first comment to until now. Actually you like to participate to told the answers for all the questions, that’s not a good. And My feedback, you not gave valuable answers like others. So please try what you have know.



Per your request, I will not offer you any future help.



Thanks for letting us know where the true problem was found. You may be able to solve your amplifier issue with an LM324 integrated circuit chip, an electrolytic capacitor, and a few resistors. As much as I would like to forget the experience; I once worked for Mamac Systems of Eden Prairie, Minnesota. Their chief engineer and owner claimed to have origins in your region of the world, just North of India. I consider his engineering experience suitable for the task, should you need to look for a consultant.

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