1 The Leader in Industrial Data Communication Solutions Troubleshooting Tips

2  General  Clarify symptoms  Isolate comms from PLC network  Perform loopback or PING tests  Check diagnostic information  If communications are verified, consider PLC system:  Improper RSLinx configuration?  Latency causing timeouts?  Program problems?

3 Larry’s Rockwell Tips  General Comments  Rockwell’s example PLC programs work very well  Noisy phone lines or less than ideal wireless links:  Greater retries (latency)  Do not exceed throughput capacity  Consolidate data to minimize number of MSGs  A few MSGs with larger amounts of data is faster

4 Larry’s Rockwell Tips  SRM Wireless Ethernet Modem  Equipment attached to remote modems do not directly communicate  Use Ethernet switches, not hubs  IGMP snooping preferred

5 Larry’s Rockwell Tips  DF1 Protocol  No limitations with Data-Linc modems  Prefer STD Polling Mode (multiple MSGs per scan)  DF1 master PLC will relay MSGs  “Missing Remote” Failure (not with Logix platforms)

6 Larry’s Rockwell Tips  DF1 Protocol  “Missing Remote” Failure (not with Logix platforms)  On SLCs do this:

7 Larry’s Rockwell Tips  NOT this: Reason:  With SLC or MicroLogix multiple enabled MSGs are queued in the transmit buffer. While queued their Timeout interval is timing. If a current MSG times out all others queued will timeout giving the appearance that multiple slaves have failed.

8 Larry’s Rockwell Tips  Multi-drop Channel Pass-Through is a wonderful thing!

9 Larry’s Rockwell Tips  Logix Platforms  These machines can REALLY move data and quickly overwhelm a radio network. As always, do not exceed the network’s throughput capability.  Be mindful of RPI. Ten 32 bit words with an RPI of 10 milliseconds is 32kbps without even considering protocol overhead!

10 Larry’s Rockwell Tips  RSLinx  Red Xs can appear intermittently when using low baud rates (1200 baud) depending on communication quality and other communication traffic. This is normal.  DF1 Polling Master Driver.  The parameters Max Pkt Wait Time (Sec) and Max Retransmission Wait Time (Sec) and not well documented.  Values that have worked well:  Max Pkt Wait Time: 8 (default 150)  Max Retransmission Wait Time: 15 (default 600)

11 Larry’s Rockwell Tips

12 The Leader in Industrial Data Communication Solutions THANK YOU!