Publication 1763-RM001B-EN-P - April 2007
Communications Instructions 371
Data Table Address/Offset
This variable defines the starting address in the target controller. The data
table address is used for a 500CPU and PLC5 type messages. A valid
address is any valid, configured data file within the target device whose
file type is recognized by the controller. Valid combinations are shown
below:
The data table offset is used for 485CIF type messages. A valid offset is
any value in the range 0 to 255 and indicates the word or byte offset into
the target's Common Interface File (CIF). The type of device determines
whether it is a word or byte offset. MicroLogix controllers and SLC
processors use word offset; PLC-5 and Logix processors use byte offset.
Modbus - MB Data Address (1-65536)
Modbus addressing is limited to 16 bits per memory group, each with a
range of 1 to 65,536. There are four memory groups, one for each
function:
• coils (generally addressed as 0xxxx)
• contacts (1xxxx)
• input registers (3xxxx)
• holding registers (4xxxx)
Coils and contacts are addressed at the bit level. Coils are outputs and can
be read and written. Contacts are inputs and are read-only.
Message Type Local File Type Target File Type
500CPU and PLC5
O, I, B, N, F
(1)
, L
(1) Message Type must be 500CPU or PLC5. The Local File Type and Target File Type must both be Floating Point.
O, I, S, B, N, F
(1)
, L
TT
CC
RR
RTC
(2)
(2) 500CPU write RTC-to-Integer or RTC-to-RTC only.
N, RTC
500CPU, PLC5 and 485 CIF
ST
(3)
(3) MicroLogix 1100 OS Series B FRN 4 or later
ST
(3)
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