Mitsubishi BIN & BCD Instruction

I am having problems understanding the Fx BIN and BCD intruction. I am writting the program and testing in on the Mits simulator program.

Am I understanding the following lines correctly.

[x0]------------------------[ bin KIX1 D0]

X1 = 1
X2 = 2
X3 = 4
X4 = 8

When x0,x1,x4. are closed k1x1 value (9) D0 value(9)
When x0,x1,x2. are closed k1x1 value (3) D0 value(3)

All works well if the value is 9 or less.

when x0,x2,x4. are closed k1x1 value(10) D0 value (16)
when x0,x3,x4. are closed k1x1 value(12) D0 value (18)

The value in D0 is alway + 6 higher.

Why is this happening , where has the extra 6 come from ?

A similar thing happens with the following line.

[x0]-----------------[bcd k1x1 D1O]

All works well up to a max of 9 .

Go above this and the simulator comes up with ( operation error )

Why does it do this ?

Sorry for the long post.

SonA

While I am not familiar with the Mitsubishi instruction set the 'K1X1' value appears to be an accurate representation of the input bits. If that were a BCD value then the D0 value appears to be a hex representation of that BCD encoded value. it's not an 'extra six'. It's the method of displaying the value of bits in a register.

Upon reading of the manual this instruction interprets the source value as a BCD, converts it to a binary number, then stores that in the destination. So it's behaving exactly the way the manual states. You get an erorr when the source is no longer a valid BCD number.

I havent checked the manual but the K1 value sets the number of bytes - i think
so you have K1 - K2 or K3 available to you
Try one of these variations as you may be seeing a 'Carry' instead.

In BCD, the value that comes after 9 is A, not 10.

http://en.wikipedia.org/wiki/Binary_coded_decimal



-Eric

iant said:

I havent checked the manual but the K1 value sets the number of bytes - i think
so you have K1 - K2 or K3 available to you
Try one of these variations as you may be seeing a 'Carry' instead.

Click to expand...

You're right, Ian. Mitsubishi groups them in 4 bit chunks. The value after K is how many groups of 4 bits, starting at the Xn register, so K1X1 would use X1 thru X4, K2X1 would use X1 thru X8, etc...

In this case, K1X1 is correct.



-Eric

It's been a long time since I did thumbwheels into a Mitsubishi, but I believe it is limited to 0-9 since that is what a thumbwheel gives by digit. the ones digit would be 0-9
the tens would also be 0-9 and you would have to multiply by 10 in the plc. this method was a big hog on inputs.

correction:

Just tried this in the simulator, If you had more then 1 digit thumbwheel, no need to do the math I described above.
I did [BIN K3M0 D0], and with m0,m3,m4,m7,m8, and m11 on Do had a value of 999. Still an input hog though!

Good point, Bob. That also explains why he gets an error when he tries to convert a BCD value of 'A' with the BIN instruction.



-Eric

Still an input hog though

Click to expand...

There are multiplex strategies for using less inputs and polling them on different scans but i prefer to wire them direct personally

Hello all,

Many thanks for every one's replies.

After reading all the replies. The penny dropped !

Some times it's hard getting information into my thick skull.

Thanks again

S on A

When you convert BCD to binary，e.g 0016 to binary, K is measured by tens, therefore if converted to binary, with each chunk 0000(00H)->1111(0FH) is measured by 16. The system will compensate it by six if converted into binary for the carrier state for tens is 'A'(1010B) state for binary. Might as well try 'H' on the input.

Well done on your comments.
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