Arduino and PLC Intragration

Using Arduino Project Guidance
1

Hello all. New to this platform but have dabbled in C years ago.

I will try to give you my application. Transmitters for things like PH, ORP and conductivity in the PLC world have ridiculous price tags associated with them. What I hope to get out of this Arduino project in the short term is cost effective transmitters to interface with my PLC project.

First and foremost is the PH probe system. ORP and Conductivity can come later as well as PWM In/Out.

Guess my question is can I use this project to get a usable 0-5 volt or 4-20ma signal to use with my PLC projects.

Hope you are all able to help.

Thanks,
onecansay.

2

A Google search for Arduino ph gave me 1.41 million hits.

This is one of the cheaper implementations: http://www.dfrobot.com/index.php?route=product/product&product_id=1025

3

Thank you for the link but what I am trying to do is use the Arduino board to send a signal as an analog output. Looks like I may have to convert the PWM digital output to a 0-10 volt signal. There is a board out there that I hopefully can use or I have found a diagram/schematic of a PWM to 4-20ma output converter.

Will the programming allow me to take the sensor input through the main board and have a usable converted PWM signal?

Remember, me is a noob when it comes to this platform.

Just trying to get things straight in my own head.

Thank,
onecansay

4

I am looking at the Uno which has six analog inputs, plenty for the four probes I would require and six PWM outputs which once again is more than enough.

Would the Uno have enough room for programming and running four probes, or even the six maximum?

Thanks,
onecansay

5

looks like the probes + board require an analog pin, so with Arduino uno, you should be able to use 6 of them

6

Thank you.

Have on the way an Arduino Uno experimenter kit along with a display.

Guess jumping in with both feet. Will have to figure out how to generate a 0-10V output from PWM pins.

This should be interesting.

onecansay

7

the ph probe will have an analog output.

the arduino will chop that into 10 bits

then output that value in analogue.

much better to use an ADC of higher value and then use a serial output to maintain the higher accuracy.

the multiple conversions will have effect on overall accuracy.

look at the teensy with it's higher ACD inputs.

8

onecansay:
Hello all. New to this platform but have dabbled in C years ago.

I will try to give you my application. Transmitters for things like PH, ORP and conductivity in the PLC world have ridiculous price tags associated with them. What I hope to get out of this Arduino project in the short term is cost effective transmitters to interface with my PLC project.

First and foremost is the PH probe system. ORP and Conductivity can come later as well as PWM In/Out.

Guess my question is can I use this project to get a usable 0-5 volt or 4-20ma signal to use with my PLC projects.

Hope you are all able to help.

Thanks,
onecansay.

sensors are not expensive.
sensors with extensive testing and commercial enclosures cost more because of the research, design, engineering and manufacturing.

but, if you look, many times the sensor is the same as you buy.

so the sensors are not expensive, the packaging is.

Please post your PLC. there is no reason you cannot use a $5 e-bay sensor with a PLC or a $2 one for that matter.

the ADC input is your real goal. if the PLC cannot accept a high value signal, then it is worthless. check other intputs. the TEENSY has a high bit ADC and can output serial. even a cheap PLC should be able to accept the serial input.

but, if your PLC has an 8bit Analog in, the Arduino will not give you an better accuracy than if you connect the sensor directly.