GE PACSystems RX7i, User Manual

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Chapter 9. Modbus/TCP Client
150 PACSystems* RX7i & RX3i TCP/IP Ethernet Communications User Manual GFK-2224Q
(Word 10) Local PLC Memory Type: Words 10-11 specify the location in the local PLC where the Ethernet
interface will store data received from the remote device Valid values for Word 10 are listed below.
Type
Value
(Decimal) Description
%W 196 Word memory (word mode)
%R 8 Register memory (word mode)
%AI 10 Analog input memory (word mode)
%AQ 12 Analog output memory (word mode)
%I 16
70
Discrete input memory (byte mode)
Discrete input memory (bit mode)
%Q 18
72
Discrete output memory (byte mode)
Discrete output memory (bit mode)
%T 20
74
Discrete temporary memory (byte mode)
Discrete temporary memory (bit mode)
%M 22
76
Discrete momentary internal memory (byte mode)
Discrete momentary internal memory (bit mode)
%SA 24
78
Discrete system memory group A (byte mode)
Discrete system memory group A (bit mode)
%SB 26
80
Discrete system memory group B (byte mode)
Discrete system memory group B (bit mode)
%SC 28
82
Discrete system memory group C (byte mode)
Discrete system memory group C (bit mode)
%S
15
30
84
Discrete system memory (byte mode)
Discrete system memory (bit mode)
%G 56
86
Discrete global data table (byte mode)
Discrete global data table (bit mode)
(Word 11) Local PLC Memory Address: Word 11 determines the starting address in the local PLC in which the
data from the remote device is to be stored. The value entered is the offset (1-based) from the beginning of PLC
memory for the memory type and mode specified in Word 10. This offset will be either in bits, bytes, or words
depending on the mode specified. Valid ranges of values depend on the PLC’s memory ranges. Be sure this
area is large enough to contain the requested data without overwriting other application data.
(Word 12) Remote Device Address: Word 12 specifies the address in the remote Modbus/TCP device. Note: The
function code determines the Modbus server address area, Word 12 is the address within this area.
(Word 13) Number Registers in Remote Device: Words 13 specifies the quantity of registers (16bit words) to
read from the remote device.
(Word 14) Unit Identifier: This field is typically used by Ethernet to Serial bridges to specify the address of a
Modbus Slave on a multi-drop link. The Modbus/TCP Unit Identifier is a special control code used in a
Modbus/TCP message block.