choosing a PLC

hi guys!

im brand new to PLC programming and I require to choose and purchase a PLC before beginning to program it, with I guess ladder logic.

the specification is that the PLC must be capable of handling voltages up to app. 230 V with about 32i/p's and 32 o/p's!

please help. regards

Greetings LLP,

Power Supply: 230 V
32/32 DIOs

Any PLC have these options. There are many other factors that direct you to the most suitable to your application.

If you provide more info, we can help better.

Regards

Since you're new to PLC programming, buy your PLC from someone local who can guide you through the learning process. The brand you choose is less important than the quality of support.

since you're new to plc's, here are a few things to consider.


new plc applications do not allow plc inputs / outputs to use 230 volts NFPA 79 - electrical standard for electrical machinery 9.1.2.1 2007 edition. "9.1.2.1 AC Control Circuit Voltages. The ac voltage for control circuits shall not exceed 120 volts, ac single phase"

NFPA70E - standard for electrical safety in the workplace also
deals with arc flash. the requirements for ppe will make you think
twice when designing a control panel.

look around for local plc distributors and brands. each brand has their own pro's and cons. how long have they been in the area? if you ask questions, do they have the answer or do they have to call you back?

regards,
james

thanks alot! urh... i forgot to mention that the voltage must be a minimum of 110 V DC, so any voltage above that is fine as an input.

Regards
LLP

230V input

Hi,

The usual input voltage in PLC is 24V DC. There is cards for 110/230V AC, but they are more expensive. I would recomend to use standard inputs and use realys for coupling.

Best Regards,
Kelkoon

thanks for all the info. Since I have searched the net high and low and could not find any plc's accepting 110V dc input, Im not sure about how to handle this problem since I havent physically been involved with PLC's before. The programming shouldnt be a problem, I just need a bearing in the right direction.


Regards
LLP

LLP said:

thanks for all the info. Since I have searched the net high and low and could not find any plc's accepting 110V dc input, Im not sure about how to handle this problem since I havent physically been involved with PLC's before. The programming shouldnt be a problem, I just need a bearing in the right direction.


Regards
LLP

Click to expand...

Just connect your 110VDC input to a relay coil, then switch 24vdc through the contact to the actual PLC input. You can normally find nice small "PLC interface relay"s that dont take up too much room.
SOmething like this will be neat and tidy:

http://eshop.phoenixcontact.com/phoenix/treeViewClick.do?UID=2966281&parentUID=204582&reloadFrame=true

Hope that helps

Depending how fast the inputs are, a relay might not be your best chose. More information is needed.

ahhh! im finally getting a bearing in the right direction..
thanks for all of the help thus far guys.. i just need to finalize some specifications and I will post up some info for further help if required.

best regards
LLP