Download EIP4CCPU User`s Manual (September 2, 2014)

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9.1.2.2.2 Explicit Message Instruction Function Block
For the user’s convenience, the explicit message has been implemented as a function block (FB) using Structured
Text programming language in GX Works2. Please contact Mitsubishi for more information regarding the Explicit
Message Instruction Function Block.
9.1.3 EtherNet/IP Server
The EtherNet/IP server supports only explicit messaging. Class 3 (explicit messaging) can serve as a direct method
of accessing the sequencing PLC’s devices by reference to “tag names”. Tags are read via the EtherNet/IP “Data
Table Read” service, and tags are written via the EtherNet/IP “Data Table Write” service. Data is read and written as
16-bit values.
9.1.3.1 Device Tag Reference:
The supported device types can be accessed with their own unique tag names with one PLC instruction. Note that
an underscore (“_”) is used to separate fields in the tag names. Tag names are generated according to the following
equation:
[device type prefix]_[ address]
The address is a 32-bit unsigned value. Note that the address may take the form of a decimal or hexadecimal value
depending on the device type. The supported device types and address formats are listed in Table 3:
Table 3: Supported Device Types
Device Type
Format (d = decimal, h = hexadecimal)
Data Register
D_<d>
Special Register
SD_<d>
File Register
ZR_<d>
Link Register
W_<h>
Examples
Access data starting at Data Register 100…….………………………….….D_100
Access data starting at Link Register 1000………………………………..…W_3E8
9.2 Allen Bradley CSP
9.2.1 Overview
Ethernet-enabled Allen-Bradley legacy PLCs (such as the PLC5E and SLC-5/05 series) use a protocol called CSP
(Client Server Protocol) to communicate over the Ethernet network. The flavor of CSP used by these PLCs is also
known as “PCCC” (Programmable Controller Communication Commands) and “AB Ethernet”. CSP by definitions is
executed with explicit messaging. Refer to the DF1 Protocol and Command Set manual for more information on
PCCC and CSP.
9.2.2 CSP Client
The CSP client follows the same behavior as the EtherNet/IP client explicit messaging. Refer to section 9.1.2.2.
9.2.3 CSP Server
The CSP server can only be accessed by explicit messaging. Similarly to the EtherNet/IP server, it can also serve as
a direct method of accessing the sequencing PLC’s devices by reference to a file number and offset. Data is read
and written as 16-bit values.
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