Rockwell Automation 1761 MicroLogix 1000 Programmable Controllers - Manual (Page 154)

Preface MicroLogix 1000 Programmable Controllers User Manual
9–6
Note To convert numbers larger than 9999 BCD, the source must be the Math Register
(S:13). You must reset the Minor Error Bit (S:5.0) to prevent an error.
Example
The BCD value 32,760 in the math register is converted and stored in N7:0. The
maximum source value is 32767, BCD.
0 0 0 3 2 7 6 0
3 2 7 6 0
5–digit BCD
S:14 S:13
0000 0000 0000 0011 0010 0111 0110 0000
N7:0 0111 1111 1111 1000 Decimal
FRD
FROM BCD
Source
S:13
00032760
Dest N7:0
32760
MPS displays S:13
and S:14 in BCD.
You should convert BCD values to integer before you manipulate them in your
ladder program. If you do not convert the values, the controller manipulates them as
integers and their value may be lost.
Note If the math register (S:13 and S:14) is used as the source for the FRD instruction
and the BCD value does not exceed 4 digits, be sure to clear word S:14 before
executing the FRD instruction. If S:14 is not cleared and a value is contained in
this word from another math instruction located elsewhere in the program, an
incorrect decimal value will be placed in the destination word.