6
MULTIMODE FOMS -ST AND -SMA
This section provides detailed information about the function of each
DIP switch position, and lists all possible settings. Use this section as a
configuration guide for applications where the FOM’s default settings
would not provide correct results. (Position 1 is reserved for future use.)
Positions 2 though 5: Data Rate (Sync. Mode)
Switches 2 through 5 determine two configuration parameters: synchronous
or asynchronous data rate and the mode of synchronization (Sync. Mode)
between two FOMs. Here’s how the packet-spacing option works: The “2X”
setting doubles the space between data packets compared to the “1X” setting,
so that each packet is more easily distinguishable from those before and after
it. This offsets some of the effects of signal degradation over distance, and
allows communication over as much as 5 km (3.1 miles) as opposed to the
“1X” setting’s limit of 2.5 km (1.5 miles). Table 3-2 at the top of the next
page shows every possible setting for these four switch positions.
Position 6: Reset
You can use position 6 to reset the MultiMode FOM without powering down
the unit. Move position 6 to ON to put the FOM in “reset conditon,” then
move position 6 back to OFF (the default setting) to put the FOM back in
“operating condition” (resume normal operation). Don’t leave position 6
ON: the FOM will not work properly unless this switch position is OFF.
Position
Function
Factory Default
1
RESERVED
OFF
2
Data Rate (Sync Mode)
ON
3
Data Rate (Sync Mode)
OFF
4
Data Rate (Sync Mode)
OFF
5
Data Rate (Sync Mode)
ON
6
Reset
OFF
Operating Mode
7
Handshaking
ON
Control Signal Mode
8
Clocking Method
OFF
Internal Clock
0 to 19.2
Async (2X)
}
Table 3-1. Summary of Switch Settings, Showing Factory Defaults
