Rockwell Automation GMLC Reference Manual User Manual
Page 416
Publication GMLC-5.2 - November 1999
Auto RIO Update
379
The four least significant digits of the magnitude are written to I/O group
6. The remaining three BCD digits are written to the lower 12 bits in I/O
group 7. The sign bit is I/O group 7 bit 17 (PLC-5) or bit 15 (SLC). This
bit is 0, if the value is positive and 1, if it is negative.
Bits 14 – 16 (PLC-5) or 12 – 14 (SLC) indicate the number of decimal
digits (digits to the right of the decimal point) in the BCD magnitude. The
motion controller automatically determines this value to maintain the
maximum number of significant digits in the displayed value. This value
typically changes from update to update. Thus, if the current position of
Axis 0 is –123.45, the output image table for rack 3 is updated as shown
below (x = don’t care):
Value is negative
O:037/17 =
1
2 Decimal digits
2
10
= 010
2
⇒
O:037/16, …/15, …/14
Magnitude
123.45 x 10
2
= 0012345
I/O Group 6
2345
10
= 0010 0011 0100 0101
BCD
I/O Group 7 lower 12 bits
001
10
= 0000 0000 0001
BCD
I/O
Group
15
(SLC)
17
(PLC)
08
10
07
07
00
00
0
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
1
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
2
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
3
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
4
x
X
x
x
x
x
x
x
x
x
x
x
x
x
x
x
5
x
X
x
x
x
x
x
x
x
x
x
x
x
x
x
x
6
0
0
1
0
0
0
1
1
0
1
0
0
0
1
0
1
7
1
0
1
0
0
0
0
0
0
0
0
0
0
0
0
1