CTI 2572-A, Installation And Operation Manual

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CTI 2572-A Installation and Operation Guide V1.3 55
CHAPTER 7. Ethernet/IP Server
7.1. Overview
Firmware versions 2.00 and above provide support for Ethernet/IP server functions. Using
Ethernet/IP, controllers such as the Allen Bradley Control Logix can read data from and write data to
505 PLCs.
General Description
The 2572-A Ethernet I/P (EIP) server allows an EIP client to access data in a SIMATIC® 545 or 555
PLC. The EIP Server supports reading data from V memory using a CIP
D
ATA
T
ABLE
R
EAD
message
and writing data to V memory using a CIP D
ATA
T
ABLE
W
RITE
message. V memory values can be
accessed as 16 bit unsigned integers, 16 bit signed integers, 32 bit signed integers, or 32 bit floating
point numbers.
V Memory Concepts
Variable (V) memory consists of a block of 16 bit registers. The interpretation of the V memory
register contents depends on the application accessing the register. V memory registers can be
interpreted as a field of 16 bits, an unsigned 16 bit decimal number, a signed 16 bit decimal number,
or a set of ASCII characters.
In addition, two consecutive registers can be combined and interpreted as a 32 bit number (signed
integer or floating point number). For example, if you were writing a block of 2 floating point
numbers to V memory starting with V memory 100, the registers would contain the following data.
V Memory
Address Data
100
101 Floating Point Number 1
102
103 Floating Point Number 2
Tag Names
Tag Names are used to specify the type of memory to be accessed, the format of the data, and the
memory locations where the data is stored. A Tag Name consists of a Tag Type and a numeric
address. The Tag Type specifies the PLC data element type (e.g. V memory) and the data format. The
numeric address specifies the address of the first data register to be accessed.
For example, the Tag Type VS would be used to access one or more V memory locations as 16 bit
signed integer values. The complete Tag Name VS100 would be used to access V memory address
100 as a signed integer value.