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Allocation Areas
1 word
Number of
allocated words
Word Allocations to Word Devices (D, T, C)
First word
Number of
allocated words
First + 1 word
3-10
F Word Allocations
When allocating bits to bit devices, the following points relating to the method of
specification must be observed.
S Points to note when allocating to M (special relays) and S (state relays)
M and S devices are bit devices expressed in decimal in the case of Mitsubishi
FX series PCs. However, inside the PC, the bits are actually managed in units of
16. Therefore, when accessing words using word allocation, make the specifi-
cation so that the first bit number is a multiple of 16.
S Points to note when allocating to X (input relays) and Y (output relays)
X and Y devices are bit devices expressed in octal in the case of Mitsubishi FX
series PCs. Therefore, when accessing words using word allocation, ensure
that the least significant two digits of the first bit number are "00", "20", "40", or
"60".
The area used for word allocation is as follows.
15
First word
First + 15 bits
First + 1 word
First + 31 bits
Word allocations to word devices (D, T, C) are described here.
It is impossible to make bit allocations to word devices.
Normally one word device occupies one word (16 bits). Therefore, when allocat-
ing a word to a word device, any number not outside the range for the area can be
specified. However, in the case of counters C200 and higher, one word device is
32 bits, i.e., it occupies 2 words. For details on the ranges of the areas within which
specification is possible, refer to "Mitsubishi FX Series PC Allocation Areas" (page
3-11).
The area used for word specification is as follows.
S Normal device
15
14
13
12
14
First + 14 bits
First + 30 bits
11
10
9
8
7
First word device (lower 16 bits)
First word device (upper 16 bits)
2
1
First + 2 bits
First + 1 bit
First + 18 bits
First + 17 bits
6
5
4
3
2
Chapter 3-4
0
Bit
First + 0 bits
First + 16 bits
1
0
Bit
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