OPTO 22 SNAP PAC R SERIES, Руководство пользователя

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TROUBLESHOOTING THE SNAP PAC R-SERIES CONTROLLER
SNAP PAC R-Series Controller User’s Guide 60
based on recent network traffic. If the network becomes busier, for example, the stack automatically adjusts
the RTO to a higher value.
If the TCP/IP stack times out while trying to transmit data, it doubles the current RTO and tries again. This
process continues for five retries; after that, the device stops trying and sends a timeout message.
If you are receiving frequent timeout messages from the device, you can change the TCP parameters in PAC
Manager.
1. Start PAC Manager:
– In Windows 7, click the Windows Start button, and then click All Programs > Opto 22 > PAC Project
10.0 > PAC Manager 10.0.
– In Windows 10, click the Windows Start button and type Opto 22 > PAC Manager 10.0.
2. In the PAC Manager main window, click the Inspect icon .
3. In the Device Name field, type the name or IP address of the controller.
Then, click Status Write.
CAUTION:
Note the following recommended settings:
If you set these fields too low, you may not be able to communicate with the device at all—even through PAC
Manager—to fix the settings. Then you would have to reset the controller to factory defaults.
4. Change these four fields as necessary:
Minimum RTO sets an absolute minimum value for the RTO. The device’s calculated RTO will never go
below this value.
Initial RTO sets the RTO for the first communication try. Be careful: since all future tries are based on this
value, if you set it too low for network conditions, a connection will never be made.
TCP Retransmits sets the number of times the device retries communication. Larger, busier networks
need a higher number of retransmits than smaller networks with less traffic.
TCP idle session timeout sets how long (in milliseconds) the device allows a session to remain open
without any activity. After this time, the device checks the session to make sure it is still good, and closes
it if it is not. The default is 240,000 milliseconds, or four minutes.
5. Click the Apply button to write your changes to the controller.
TCP Minimum Retransmission Timeout (msec): 250
TCP Initial Retransmission Timeout (msec): 3000
TCP Retransmission Attempts: 5
TCP Idle Session Timeout (msec): 240,000