ProSoft Technology PS-QS-1x10-0781 - Manual (Page 58)

FieldServer Configuration Manual Page 58 of 90
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appropriate moment, and for their duration prevent reception of data. Squelch_Timer_Tx starts at the end of a
transmission (as defined by RTS becoming inactive), and Squelch_Timer_Rx starts at the end of a valid received
message (as determined by the protocol driver). Note that the Squelch_Timer_Rx is only relevant to Servers as
Clients will in any event disregard any spurious data received after a response.
Master
Slave
Legend:
Line_drive_on
Line_drive_off
Squelch_timer_TX
Squelch_timer_RX
Turnaround_delay
Poll_delay
Squelch received by master after
poll.
Deleted by Squelch_timer_TX
Squelch received by master after
response.
Deleted by Kernel before next poll
Squelch received by slave after poll.
Deleted by Squelch_timer_RX
Squelch received by slave after
response.
Deleted by Squelch_timer_TX.
10
9
8
7
6
5
4
3
2
1
RTS
TX
RX
RTS
TX
RX
6 3 2 1
Next Poll Poll
Poll
Response
Response
7 8
2 1
9 10
4
5
3
Figure IX: Timing Diagram: Line Drive On/Off, Tx and Rx Squelch, Poll Delay, Turnaround Delay.
Note: Squelch_Timer_Tx and Squelch_Timer_Rx are not supported in the FS-X30 Series.
9.2.1 Setting Parameter Values
It is important to prevent the squelch suppression times from overlapping with valid data and interfering with
proper communication. The following connection parameters can be configured for the FieldServer:
Turnaround_delay This is the time the Server takes to initiate a response after having received a poll. The Client
connection must have a Squelch_Timer_Tx value less than the turnaround delay.
Poll_Delay This is the shortest time the Client will wait between receiving a response message and
initiating the next poll. The Server connection must have a Squelch_Timer_Tx value less than
the poll delay.
Example:
Connections
Port , Squelch_Timer_Tx , Squelch_Timer_Rx , Turnaround_Delay , Line_drive_On , Line_drive_Off
P1 , 0.06 , 0.01 , 0.050 , 0.001 , 0.001
9.2.2 Statistics
Each connection keeps track of the number of bytes suppressed as a result of TX and Rx squelch timers. These may
be viewed in the connection statistics screen.