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hi this is Tim here we are on the backside of a trainer and here is our analog display you can see I haven't wired down these terminals right here and for a milliamp signal we're actually gonna use our analog simulator in current source mode because it's just a little easier to control compared to the potentiometer and I can show you a few things that'll help you understand exactly how a milliamp signal is read by a PLC and we're gonna start the basics just like this shows we're gonna have our 4 to 20 milliamp output which is going to be our analog simulator and we're gonna have our 4 to 20 milliamp input which is going to be our meter and right here is the plus and minus for our milliamp meter and they go down to terminals 2 & 3 and that is our plus and minus so we're gonna connect the red wire off of our meter to the red hose of our analog simulator and we're going to connect the black wire of a meter to the black wire of our analog simulator and that's all it takes so as we bring the signal up it starts an increment and over there and there you go it shows 20 milliamps on our analog simulator and 20 milliamps on our display but now I want to do a little something to show you a little more about how it works and we're gonna come over here on the backside of our trainer and we're going to add an additional circuit and just the same as you were adding a little display to a millionth circuit you don't type parallel like you would a voltage signal you want to cut into the circuit and you add something into some add two terminal blocks to our trainer and on your typical analog device it's gonna have a load resistance and what that is is it's a load that they put into that analog circuit so they can read it and I'm going to show you through this that what they're doing is they're actually using that load resistor and Ohm's law to read a voltage signal on the milliamp sir so right here I have a 250 ohm resistor which is a fairly common resistor for an analog circuit and what I'm going to do is I'm going to connect it across the two terminal blocks that I've added now what I'm gonna do is I'm going to take a red wire off for the analog simulator you see I think it loose and show an open wire now and I'm going to connect it to one of these terminal blocks now I'm going to take the other terminal block connect a wire to yeah and I'm going to connect it back to our analog simulator now live environment away on an analog simulator and also over here you can see we're showing twenty million but what we've done is we've added another load into our circuit and with that you can take the same solve pie chart and calculate the voltage that's going to be across that resistor I'll put a link to this in the description but mainly okay we're looking for voltage and so that is e and highlighted yellow in this chart and so then you can go all for that into the areas from 6 o'clock to 9 o'clock and figure out okay what do we know well we know our milliamps and we know our resistance so we take our current milliamp signal which is 20 milliamps and we multiply it by our load resistor which is 250 ohms then we can come out with that we should have five volt across this terminal so here I have a voltmeter and we're gonna put it across it and there you go we have five volt of process and that is how I feel see or in any milliamp input actually read the signal it doesn't really read a milliamp signal as it reads the voltage across the load resistor so now let's take it one step further let's get it over on our digital display where we can look at the milli amps and volts at the same time now to do this I'm gonna have to make a couple modification right now this is not common for a 24 volt power supply so we're going to tie the minus of this milliamp signal to the common of our 24 volt power clock so that we can use our alternator and often step-by-step instructions in the description on how we did all this then we're going to take our voltage term which is terminal number 1 our trainer and we're going to connect it to the second terminal that we added so now we can see we have 20 milliamp here we have 20 milliamp here and we have 5 volt so I've created this spreadsheet right here and you can see the exact voltage that it should be so let's go to 16 millions and at 16 millions we should show or bolt on our leader all right 16 milli amps here 16 milli amps here 4 volt there next let's go to 12 million so now we have 12 milli ampere called milling updater 3 volts and you can keep doing this and let's just go on down to 4 million now we have formerly up here we have 4 Lily up here and we have 1 volt there so that is how a PLC actually reads an analog signal is it takes that load resistor and calculates the new amps based off of the voltage that you have now there are other resistor values that are used besides 250 ohm I just use to it because it is kind of a common one another thing if you see a signal that is 2 to 10 volt chances are that is a million signal with 125 ohm resistor now one tip I will give when you think about adding devices into an circuit is typically a thousand aims it's about all you can drive and we're gonna do another video that kind of goes through why that is and why there are limits on load resistance this video has been helpful please like this video if you liked it be sure to subscribe till next time hi this is Tim and this is amber of TW controls we run the automation store be sure to subscribe for more great videos and like this video and comment on what you would like to see next visit our website where we offer a full line of PLC's simulators control panels PLC trainers and more