Instruction manual
Glossary
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Outbound Address
Range High
Parameter used for store and forward radio
communications.
Outbound Address
Range Low
Parameter used for store and forward radio
communications.
Percent Change Delay
A value used with analog inputs or outputs to determine
when to report an exception or log data.
Percent Change
Threshold
A value used with analog inputs or outputs to determine
when to report an exception or log data.
Phone line
A dial-up telephone line.
Phone modem module
A module that provides the interface between the RTU and
a dial-up telephone line.
PLC
Programmable logic controller. A small industrial device
that originally replaced relay logic. Usually uses the
MODBUS protocol for communications.
Poll Cycle Interval
For autopolling, this is the time between successive polling
cycles, defined as the time between the end of one autopoll
cycle and the start of the next.
Polled-only system
A SCADA system in which the master controls all
communication. The RTUs only transmit in response to a
poll (query) from the master.
Polling
Refers to the communications from the master to query the
status of inputs on RTUs.
Polling communications
failure
A polling communications failure occurs when an RTU
does not receive a poll for a programmed period. A local
logic program uses a built-in variable, LastPollTime, to
detect this type of communications failure.
Power-Up Message
A message (e.g., product name, version number, etc.) sent
by the device to its Port1 serial port on power-up.
Protocol
A set of conventions governing the format and timing of
message exchange between two communications terminals.
Radio interface module
A module that provides the interface between the device’s
core module and the radio transceiver. Also called “radio
modem.”