12V Signal to 24V Switch

Thread Starter

Goerge99

Joined Mar 18, 2008
3
Good day.

I wonder if anybody out there can help me out.
I have a 12 Volt signal coming from a field device into a PLC.
The problem is, the field device is a 12 volt signal, and my PLC is a 24 volt.
How can I get a 12 volt signal to switch a 24 volt signal?

Is there any clever, yet easy way of doing this?

Thanks for your Help.
 

Thread Starter

Goerge99

Joined Mar 18, 2008
3
I have tried to switch a 24 volt supply with the use of a diode, and a 9 volt battery.

But I can seem to get it correct, nothing happens. The diode doesn't even blow...
 

KMoffett

Joined Dec 19, 2007
2,766
Could you give us a little more detail? A schematic, a link to info on the PLC and the field device? My guess is that two transistors and three resistors, or a small MOSFET relay and two resistors would do it, but not knowing any more than I do now, I'll stop here.

Ken
 

Pich

Joined Mar 11, 2008
119
Usually a PLC will have a 24V source, if speed is not an issue you could use a 12 volt relay and 24 v on the contacts or a solid state relay as mentioned earlier.
 

Thread Starter

Goerge99

Joined Mar 18, 2008
3
The PLC range I'm using is a Delta PLC, the module has a sink and source function, depending on how it is wired.
I'm trying to source on the PLC.

There is a sketch attached.
The diode Number: IN4007

Treat the lamp in the sketch as a input to the PLC.

Thanks
 

Attachments

KMoffett

Joined Dec 19, 2007
2,766
"Delta PLC" is not enough info...do you have a model #? "Sink" and "Source" are usually output functions, not input. Though this might refer to pulling the input high or low. The manual should clear this up if we can get to it. :)

Ken
 

techroomt

Joined May 19, 2004
198
realize that you connect a sourcing field device to a sinking input, and a sinking field device to a sourcing input. quite a plc if an input channel can be user customized to either function. regardless, use a relay (12vdc coil and 24vdc power source) interfaced to the plc input. and as mr. pich has mentioned, you will have additional propogation delay of the relay, and some plc's (usually micro's) source a 24vdc for field device inputs, some don't.
 

KMoffett

Joined Dec 19, 2007
2,766
technroomt,

I assume that the terminology is for industrial controllers. Since that is not my field, do you have a link or reference that I can persue?

Ken
 

thingmaker3

Joined May 16, 2005
5,073
Delta has manufactured many models of PLC. Do you know which one you have? Some of them are capable of accepting 12V input.
 

mrmeval

Joined Jun 30, 2006
833
If you have or can acquire the manual for it you'll probably find it can handle a range of values. Some PLCs can be set for what voltage you want it to detect.
 

KMoffett

Joined Dec 19, 2007
2,766
techroomt,

Thanks, I'll check it out. I don't know what I would do without the internet...haunt libraries like I used to do, I guess. ;)

Ken
 
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