Omron C200HW-CLK21, CVM1-CLK21 Network Parameters, No. of Polled Nodes per Communications Cycle

Communications Mechanism Section 8-1

If the node is always to be connected as a polled node when the power is turned on, set it as a polled node. If the node can become a polling node when the power is turned on, set it as a polling node. One of the nodes set as a polling node will serve as the actual polling node. Except for maintenance after Unit replacement (see 9-6 Handling Precautions), set the Units all nodes as polling nodes (set the polling node/polled node bit to “0”).

8-1-3 Network Parameters

Network parameters are also used to control network operations. Network parameters are read from the polling node and distributed to all other nodes when the Controller Link Network is started. In this way, all nodes on the net- work always have the same network parameter settings. If nodes are con- nected to the network halfway during network operation, the network parameter settings will also be distributed to these nodes when they are con- nected. The following three network parameters can be specified.

Maximum Node Address This parameter specifies the maximum node address of nodes to be checked by the polling node. The default is 32. (See note.) Reducing the setting of this parameter reduces the number of nodes checked by the polling node and can thus avoids unnecessary check operations. However, if the network contains nodes with node addresses greater than the setting of the parameter, these nodes will not be connected to the network.

No. of Polled Nodes per Communications Cycle

Note The default maximum node address will be set to 62 when the Wired Network 62 Node Enable Bit in the DM Parameter Area software switches of the CS1W-CLK21-V1 or CJ1W-CLK21-V1 Unit is ON and the Unit is restarted.

This parameter specifies the number of nodes to be checked (polled) by the polling node during each polling cycle. The default is 4. Setting this parameter to a high value increases the communications cycle time, but reduces the time required to recognize that nodes have been removed from or added to the network. Reducing the setting of this parameter shortens the communications cycle time but delays a network response when a node is disconnected from or connected to the network.

No. of Event-frames per This parameter specifies the maximum number of event frames (communica-

Communications Cycle tions other than data links, such as message service transmissions) that can be transferred during a communications cycle. Specify a value in units of 128 bytes. The default is 35 (128 ⋅ 35 = 4,480 bytes).

Increasing the setting of this parameter increases the communications cycle time but allows for more event communications such as the message service. Too small a parameter value restricts event communications, resulting in an error. See 8-2 Communications Cycle Time (on page 251) for the effects of network parameters on communication cycle times.

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