Delta RMC151 - Manual (Page 451)

6 Communication
• The RMC handles incoming packets on a first-in first-out (FIFO) basis, making it
possible to send multiple requests and then wait for the replies.
• The RMC can handle up to 64 open TCP/IP connections at once. Typically each device
uses one connection at a time, allowing the RMC to be connected to up to 64 devices
at once.
• Multiple-register reads and writes are limited to 100 16-bit words for writes and 125
16-bit words for reads—per the Modbus/TCP specification—even though the length
field in the Modbus/TCP header makes it look like larger packets would be supported.
• Floating point numbers are 32-bit values and use two (2) holding registers each. The
least significant 16 bits comes first.
6.8.10.2. CSP
This is a proprietary protocol developed by Allen-Bradley, Inc. Variants of this are used on
Allen-Bradley's SLC 5/05 and PLC-5 controllers. This protocol is also used by the Allen-
Bradley's SoftLogix 5 and RSLinx and SoftPLC Corporation's SoftPLC. Allen-Bradley does not
publish the specifications for this protocol.
The CSP protocol is also known as "DF1 over Ethernet". It uses the same addressing format
and function code types as the serial DF1 protocol. This common component is called PCCC.
CSP can be used to read and write any registers in the RMC. In the Allen-Bradley PLCs, MSG
(message) blocks are used to read and write any registers in the RMC using CSP. See Using
Allen-Bradley Controllers via Message Block for details.
Supported PCCC function codes:
• Diagnostic Status (06 03)
• Echo (06 00)
• SLC Protected Typed Logical Read with 2 Address Fields (0F A1)
• SLC Protected Typed Logical Read with 3 Address Fields (0F A2)
• SLC Protected Typed Logical Write with 2 Address Fields (0F A9)
• SLC Protected Typed Logical Write with 3 Address Fields (0F AA)
• PLC5 Typed Read (0F 68)
• PLC5 Typed Write (0F 67)
• PLC5 Word Range Read (0F 01)
• PLC5 Word Range Write (0F 00)
Addressing:
Same as DF1 (serial) - see the DF1 Addressing topic.
6.8.10.3. FINS/UDP
The FINS/UDP protocol is an Omron protocol which can be used by a PLC program to transfer
data and perform other services with a remote PLC connected on an Ethernet Network. The
FINS protocol allows Omron PLCs to communicate with the RMC75E or RMC150E. The RMCs
support FINS/UDP.
The FINS/UDP protocol is an open application protocol developed and used by Omron
Electronics Inc. This protocol is available over a number of media, including Ethernet and
serial. Additional information is available in the CS1 Communications Reference Manual,
available on Omron's web site: http://www.omron.com/oei.
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