Delta RMC101 - Manual (Page 350)

RMC100 and RMCWin User Manual
5-100
5.2.6.3.3 Establishing Multiple I/O Connections with a Single RMC
Each RMC can support I/O connections with up to four EtherNet/IP clients such as the
ControlLogix 1756-L1. Each connection in an RMC must use the same RPI and Input Data size.
Also, only one of these can use a controlling connection. The rest must use Input Only
connections.
A controlling connection is one that has both input and output data. The output data (from the
client) contains commands that the RMC will process. The output data also includes PLC status
information that is used for detecting when the client switches from Run to Program mode. See
Handling Broken I/O Connections for details.
An Input Only connection is one that has only input data. The only output data sent to the RMC is
a heartbeat frame used to detect connection time outs.
For more information on I/O connections see Controlling the RMC over EtherNet/IP I/O.
In the ControlLogix, a controlling connection is set up by selecting the Data - INT format, and an
input only connection is set up by selecting the Input Data - INT format.
Example:
Suppose three EtherNet/IP clients want to access the data for the first four axes of an RMC. As
required by the RMC, only one of these controllers will have a controlling connection. The fastest RPI
required in this application is 10.0 ms.
The controlling EtherNet/IP client will have a controlling connection (Data - INT format in RSLogix
5000). Because this connection will access four axes, the Input size should be 41 words, and the
Output size should be 25 words. An RPI of 10 ms is used.
The other EtherNet/IP clients can now also be configured to access the same RMC, but they must
use Input Only connections (Input Data - INT format in RSLogix 5000). They must also use the same
RPI (10 ms) and input size (41 words).
Suppose that one of these EtherNet/IP clients also wanted to monitor the fifth axis, even though it is
not controlling that axis. This would require increasing the Input Size from 41 to 51 words on all
controllers accessing this RMC's input data.
5.2.6.3.4 Controlling the RMC over EtherNet/IP I/O
As described in the Configuring an RMC EtherNet/IP I/O Connection for the ControlLogix and
RMC EtherNet/IP Object Model topics, each RMC can have I/O connections open with up to four
EtherNet/IP clients (such as the ControlLogix PLC). Only one of these connections can produce
data for the RMC to consume. All of these connections will consume data produced by the RMC.
The following diagram shows three clients accessing a single RMC: