Operator Binary Interface

I'm trying to interface to a laser and do program selection w/o a PLC.

I'm trying to select programs 1-32 and it's a binary format. Mistakingly we bought 2 thumbwheel switches to have the 2 digits and the output was BCD which once you get to 10 is different than binary.

Wondering if anyone might know of a hardware solution to convert BCD to binary or of a Operator interface that I can select a numeric value and output the binary values.

BCD is binary, but is restricted to the decimal values of 0 - 9 because the decimal value is coded in binary. If you are looking for true 4 bit binary switches, you need to get a switch that is capable of outputting those values. You do not need to convert BCD to binary unless you input the BCD value into a PLC and then need to use it as binary once in the processor. In that case, there are instructions in most PLCs that will convert for you, but I do not believe this is what you are seeking from what you said in your post.

Now to select programs or anything else with a thumbwheel type switch from 1 - 32 you will need a switch that has more than 4 terminals since that will only take you from 0 - 15. Getting up to 32 in binary takes bits, 1,2,4,8,16 and this is only 0 - 31, so to get to 32 you have to have a 6th bit. Good luck!

You could build a circuit with ICs to do the conversion.

I'd recommend just buying the proper thumbwheel switch though... :nodi:



-Eric

If I could find the proper thumbwheel switch I'd be all over it, but I can't find anything that is true binary and not BCD.

Use 0-7 on the low order switch. Only wire the lowest 3 outputs. Then use 0-3 on the high order and wire the lowest 2 outputs. Now write up a simple table for the decimal to octal conversion and post it by the switches.

 

 Number   High Switch   Low Switch

 

 0-7          0           0-7

 8-15         1           0-7

 16-23        2           0-7

 24-31        3           0-7

 

 

You want the operator to actually have to read? This is automotive... they don't do that

The w/o a PLC part is gonna make it hard to achieve without custom building something. Why not get a Micrologix1000 and use it for a BCD to binary converter?

I see your dilemma... And see no 'simple' solution...

Similar to Bernie's idea, you could use hex thumbwheels and get from 00 to 1F. In this case, since you're only using 0 and 1 on the upper digit, it could be replaced with a toggle switch to select between the two 'banks' of programs (0-15 and 16-31).

Realize that although you can add a stop to limit the upper digit to a range of 0 to 3, you can't prevent someone from selecting programs 32 through 39. Your laser will 'see' these as programs 0 through 7...