10/27/2019 8:56 PM | |
Joined: 5/22/2017 Last visit: 9/13/2022 Posts: 51 Rating: (1) |
Thanks for the response already the sensor have convertor PT100 RTD to 4-20mA convertor is consider as inbuilt |
10/27/2019 9:58 PM | |
Joined: 5/22/2017 Last visit: 9/13/2022 Posts: 51 Rating: (1) |
my question is analog input will not work direct 4-20mA |
10/27/2019 10:02 PM | |
Joined: 12/18/2014 Last visit: 9/22/2024 Posts: 33817 Rating: (4201)
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Did you not understand my answers? The analog inputs don't work directly with 0/4 to 20 mA. |
10/28/2019 12:26 PM | |
Posts: 49 Rating: (5) |
6ED1052-1MD08-0BA0 only support 0-10V for analogue input (up to 4 analogue input). If you want to input 0-20mA, 4-20mA or PT100 input, you'll need other expansion modules. There are also 3rd Party converter (4-20mA -> 0-10V) you can use. |
10/28/2019 1:20 PM | |
Joined: 12/18/2014 Last visit: 9/22/2024 Posts: 33817 Rating: (4201)
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So as I wrote, it works also with a 500 Ohm resistor as converter. |
10/29/2019 8:47 AM | |
Posts: 49 Rating: (5) |
https://www.omega.co.uk/techref/das/4-20ma.html Practical exampleFor this example, we will assume that a 0-10Vdc input will be used to measure 4-20ma signal.Ohms law states: R=V/I where V is the Voltage, I is the current and R is the resistance R=10V/.020A = 500 Ohms When 20ma flows through a 500 Ohm resistor, it will drop 10 volts When 4ma flows through a 500 Ohm resistor, it will drop 2 volts Therefore, 4-20ma signal through a 500 ohm resister will drop 2 to 10 volts One more important thing to remember is that the resistor tolerance should be 1% or less; preferrably 0.1%, since errors in the resistance will result in errors in the voltage drop. You don't want a resister that fluctuates much with time or temperature, as it will effect your accuracy. After you have selected a resistor value, you must verify your readings and make any fine tuning adjustments in your software to compensate for any errors in the resistor. For example, a 500 ohm resistance may actually be 497.5 ohms, therefore your voltage output will actually be 1.99 to 9.95V and not 2 to 10V as we calculated. You simply connect the resistor across the voltage input terminals for your data acquisition system, and then connect your 4-20ma signal to the same two terminals, so that as the current flows through the resistor, a voltage will be dropped and then measured by the data acquisition device. Keep in mind that it may be necessary to ground the power supply if you are using it to |
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