
13–14 PLC Addressing
Publication
17706.5.16 - October 1996
Important: If the value of the mask or a level of the address is
greater than or equal to 255, then you cannot encode it
into 1 byte. You must flag this case by programming an
FF hex at the level address to signify that the level
address is greater than or equal to 255 and the next 2
bytes contain the level address. Then code the level
into the following two bytes.
The following figures show examples of PLC-5/250 logical binary
addresses.
PLC5/250 Logical Binary Address to access the LP address 1N5:300
Byte
1
2
4
5
11 1 1100
01 1 11 100
00 0 00 000
00 0 00 100
300001000
600010100
711111111
810110000
9
00 0 00 100
Byte 8 + Byte 9 = 300
mask
byte: indicates the module ID byte and 5 levels of
addressing will be encoded.
1
level 1 (value = 2)
level 2 (value = 0)
level 3 (value = 1)
module ID byte (LP) = (class x 10) + pushweel (value = 31)
level 4 (value = 5)
level 5 flag (value = FF hex)
(44 - lower byte of word)
(256 - upper byte of word)
PLC5 Logical Binary Address to access the RS address I:007
1
2
4
00011100
00000100
level 2 (value = 1)
0001110 0 level 3 (value = 7)
3 00000 100
level 1 (value = 1)
Byte
mask
byte; indicates 3 levels in the address
PLC5/250 Logical Binary Address to access the LP address 2F0:0
1
2
4
5
10 1 01 100
10 0 00 000
level 1 (value = 2)
00 0 10 000
level 5 (value = 0, the default, but must be00 0 00 100
level 3 (value = 4)
300001000
encoded because it is the last level)
Byte
mask
byte; indicates the module ID byte will be encoded
and there are 5 levels in the address. Levels 2 and 4 use
the default (0). Therefore, only levels 1,3, and 5 will be en
coded. Even though level 5 is a 0, it must be encoded, be
cause it is the last level in the address.
module ID byte (LP) = (class x 10) + pushwheel (value = 32)
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