connect keypad with plc

strantor

Joined Oct 3, 2010
6,782
The reason nobody has replied to your post is that it's disappointingly vague. How is anybody possibly supposed to help you with the amount of information you've provided? What type of PLC? what keypad? What are you talking about? These are questions which should not have to be asked.
 

Thread Starter

ahmedalsh40

Joined Dec 20, 2009
14

strantor

Joined Oct 3, 2010
6,782
the plc used is ls master k 120s(e)
type of keypad is matrix keypad
http://www.8051projects.net/keypad-interfacing/keypad-schematic.gif
i went connect it direct with plc
Ok, your drawing is a little confusing to me, so we both need to understand that the "pushbutton" symbols you have drawn are actually a voltage source; so for example, if you push "7" (SW8), you will have voltage output to column 4 & row 2. Assuming there's no keypad backlight, Your keypad should have 9 pins. The Common (9th pin) is missing from your drawing; this where your +24v will go. The other 8 pins will go to 8 digital inputs. you will then write your code to take a combination of row & column to make a number.
Rich (BB code):
Example (assuming you're using ladder logic):
|                                               |
|---| |---| |--------------------------( )------|
|  col3   row2                          6       |
 

Thread Starter

ahmedalsh40

Joined Dec 20, 2009
14
Your keypad should have 9 pins. The Common (9th pin) is missing from your drawing; this where your +24v will go. The other 8 pins will go to 8 digital inputs. you will then write your code to take a combination of row & column to make a numbe[/CODE]
any solution if keypad with 8 pins only ??
 

strantor

Joined Oct 3, 2010
6,782
can you post a link to this keypad? I've never heard of one that has only 8 pins so I could only advise you if I know what I'm dealing with. If the keypad is exactly as you drew it, it is impossible for it to work.

EDIT: If you haven't bought it yet, why don't you just buy a proper 9-pin keypad?
 

strantor

Joined Oct 3, 2010
6,782
both the link you posed and the image are not very helpful. I was hoping to see some kind of wiring diagram in a datasheet. I searched myself for these 8 pin keypads and all I could come up with was the same unhelpful things you have shown me. Going alone on what I have seen here, I don't know what advise to give you other than to buy a legitimate 9 pin keypad. If there is a way to make these 8 pin keypads work, I don't know it; I still stand by my original assessment that it's impossible until someone proves me wrong.

EDIT: the image you posed is of a 12 button keypad; not a 16 button keypad. I have been searching for 16 button keypads. the 8 pins will work for a 12 button keypad, with pin 1 as the power.

EDIT2: Just noticed that the keypad in the link is also a 12 button keypad. If you want a 12 button keypad then revert back to my original post, it explains how to use it.
 
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