Omron CJ1W-DRM21 Operation Manual page 203

Precautions for Correct Use Precautions for Correct Use
The message service function does not guarantee that a given message will reach the remote
node. Messages may be lost during communication due to noise, etc. When the message ser-
vice function is used, normally the node that issues an instruction performs resend to avoid the
above condition. With the SendCmd instruction, the resend process is performed automatically
when the number of resends is specified. For the number of resends, be sure to specify a value
other than 0.
CJ-series DeviceNet Units Operation Manual for NJ-series CPU Unit(W497)
6 Message Communications
6
6-15