0-5vdc PLC Help

I have a temperature sensor that runs from 0-5vDC. I would like my computer to be able to turn on 3 different cooling fans at the different volts as the temperature comes up is there anything that can do this?

Since you say you want to use your computer you will likely have to use some sort of programming to accomplish this. Assuming you have a Windows machine, the most likely candidate is Visual Basic.

I'd look to this sight for the hardware to read the 0-5V:
http://www.mccdaq.com/

I believe their hardware comes with drivers for Visual Basic.

Or maybe I missed something of your request.

I don't have to run this with my computer. I could do this by monitoring the voltage and then have a unit turn the fans on if that is easier. I am looking for something that is easy to use and cheap so to speak.

Steve 101 said:

I don't have to run this with my computer. I could do this by monitoring the voltage and then have a unit turn the fans on if that is easier. I am looking for something that is easy to use and cheap so to speak.

Click to expand...

In that case, the easiest is likely a display with set point outputs. Red Lion is popular but Manu companies make them. You will need to check the data sheets to make sure it will handle the 0-5V input, has the right number of outputs and has an output rating that can switch the current of the fans (or be compatible with the fan relay or starter)

1) There's "DC input alarm" modules. API handles a dozen different models, but none with 3 alarms/3 relays. So you'd have to get a dual input alarm module and a 2nd single input alarm module. Depending on style, they either mount on a socket or directly to DIN rail. The advantage is that the setup is defining the input range and defining the setpoint with some kind of DIP or rotary switches or screw driver pot adjustments. Sometimes the distributor or factory will do that for a minor fee.

http://api-usa.com/signalconditioners_alarms.php

2) Another category of devices called 'single loop temperature controllers' can have a control relay and a couple of alarm relays. Each relay has an adjustable setpoint at which it closes the relay.

These devices are always made to take a thermocouple directly with has a millivolt signal, but I suspect someone makes a unit that can handle 0-5vdc.

One issue is that they're configured from the keypad, but the setup can be somewhat cryptic, with 7 segment LEDs forming unusual characters.

And they're all designed for panel mounting.
Cal, Omron, West, Watlow, are several names that come to mind.

Another solution is to use a Click analog version. Two 0-5VDC analog inputs, and 4 outputs (DC or relay).

http://www.automationdirect.com/adc...Series_PLCs_(Stackable_Micro_Brick)/PLC_Units



-Eric

or use an arduino
it has many analog inputs and can control the fans with pwm.

+1 for arduino
you could do it for under $30!