02-13-2017 05:32 AM
help me.. my current censor acs712 i need signal conditioning for input to PLC 10v anyone can help me?? how can i use? should i use op-amp? can teach me type of op-amp and how many resistor and capasistor?
thanks
02-14-2017 08:51 AM
Hi,
I can try to help here though we do not directly make PLC's. The datasheet I found for the ACS712 is here:
file:///C:/Users/astegema/Downloads/ACS712-Datasheet.pdf
From this I can see that this sensor takes the input current and converts it to a proportional voltage output. If the input range of your PLC is 10 Vdc then you may not be making full use of the analog-to-digital converter and would want to amplify the output signal (if in the case it is outputting in the milli-Volt range). You can apply an op amp in the "voltage follower" topology here to get an amplification of the signal. There are various schematics for this that can be found online and it should detail all of the necessary resistors, etc. If you look, you will likely find the entire solution on an IC so it would just be a matter of supplying power to the chip.
02-14-2017 10:38 AM - edited 02-14-2017 10:44 AM
The sensor has a span of 2V (1.5V to 3.5V) and a bias of Vcc/2 = 2.5V
For 0-10V you need a gain of 5
An OP (assumed supply voltage 24V 🙂 ) that can go down to zero (so look for a Rail to rail output)
Here is a quickshot , not full span*, but you would need a calibration anyway... but uses E-series resistors 🙂
green plot the V2 (input) voltage, blue the output
*) sell it as a feature : Out of range can be detected 😄
But you should think about a differential input and output ... and if you do the design well, small variances of the Vcc/2 are compensated 🙂