User manual

Toolbox 32 User Manual 1.47d www.cse-semaphore.com/mykingfisher
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114
Polling After Data Has Expired
If an outstation RTU has exception reported to the master RTU recently, it is not necessary to poll the
outstation RTU until the data is older than X minutes (where X is ideally a SCADA setpoint with a default
value of say 30 minutes). If exception reports are generated frequently, it may never be necessary to poll the
outstation RTU. Communication statistics are still accumulated as a success is recorded for each exception
report received. Communication Fails are also recorded as the master will still effectively check comms every
X minutes if it has not heard from the outstation RTU. Note: the registers that are exception reported should
be the same as the registers that are polled. If a Maximum Quiet Time setpoint is used, this should be
loaded with a default value on the first ladder scan.
Advantages:
• Minimises communications over the network.
• User can set the maximum age of data before a poll.
Disadvantages:
• Takes more effort to test.
│ │
├Poll Outstation RTU If Maximum Quiet Time (#R41) Is Exceeded ┤
│ │
│DoEvery1Min R2QuietTime R2QuietTime │
│ #YTICK.MIN #R42 #R42 │
├─────┤ ├──────────[<]────────────────────────────────────────────────(Inc)────┤
│ 65535 │
│RTU2NewData? R2QuietTime │
│ #YLUPDC2 #R42 │
├──[CHANGE]──────────────────────────────────────────────────────────(Copy)────┤
│ 0 │
│R2QuietTime P3 Waiting Poll RTU2 │
│ #R42 #YPST3.2 RTU 2 │
├─────[>]─────────────────────────────────────────────────┤/├────┬──(RX_DATA)──┤
│ #R41 │ #R1 │
│ │R2QuietTime │
│ │ #R42 │
├ ┼ ┼ ┼ ┼ └───(Copy)────┤
│ 0 │
│ │
Figure: Polling An RTU After No Exception Reports For X Minutes. Note: Replace P3 Waiting #YPST3.2 with
RTU2 Waiting #YLST2.2 if using an Ethernet port.