OPTO 22 SNAP-PAC-S1, Руководство пользователя

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TROUBLESHOOTING
SNAP PAC S-Series User’s Guide
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TCP Initial Retransmission Timeout 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 Retransmission Attempts sets the number of times the controller 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 controller allows a session to
remain open without any activity. After this time, the controller closes the unused session. The
default is 240,000 milliseconds, or four minutes.
5.
Click the Apply button to write your changes to the controller.
6. In the Operation Commands list, highlight Store configuration to flash. Click Send Command.
7.
In the Operation Commands list, highlight Restart I/O Unit from powerup. Click Send
Command.
The new TCP parameters are set.
Communicating on a Serial Network
If a SNAP PAC S-series controller fails to connect using either an RS-232 serial interface for PPP host
communication or an RS-485 serial interface for I/O unit communication, check the following:
Indicators —Depending on the port(s) being used on a SNAP-PAC-S1 controller, LED S0, S1, or S2
should be red (for receive data) and green (for transmit data). On a SNAP-PAC-S2, there are separate
LEDs for Transmit and Receive for each port. Green indicates activity.
Power —Make sure that both the controller and the device it is connected to have been turned on.
Physical Connections —Check that the connectors on each end of the serial link are firmly
attached to the controller and the other connected device.
RS-232 Configuration —RS-232 communication on a SNAP PAC S-series controller is configured
using PAC Manager software, and ports must be configured correctly for their use, or they won’t
work. See “Configuring Direct Communication to Serial Devices” in the
PAC Manager User’s Guide .
NOTE: Port 0 is set by default to communicate using PPP. If you’re connecting to serial devices with Port 0,
you must change its configuration in PAC Manager.
RS-485 Configuration —On a SNAP-PAC-S1, RS-485 serial network bias and termination are
configured using DIP switches on the top of the unit. Confirm that DIP switches are set to the correct
positions for the controller’s location in the RS-485 network. See
“RS-485 Connections” on page 18
for information. On a SNAP-PAC-S2, all port configuration is performed using PAC Manager. See the
PAC Manager User’s Guide , form 1704.