ZETRON 1708 - MODBUS Protocol Explained

Glossary
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Interpreter
A method of computer programming where an intermediate
language is used.
Key Down Delay
Delay between the end of a radio transmission and the time
the radio is unkeyed.
Key Up Delay
Delay between the time the radio is keyed up and the start
of data transmission.
Leased line
Permanent wireline connection between Controller and an
RTU. Also called “private line.”
Low Threshold
A value used with analog inputs or outputs to determine
when to report an exception or log data.
Master
General SCADA term for the central control (hardware and
software) of the system. See Slave.
MODBUS
MODBUS is an industry-standard process-control protocol
used to transfer commands and data.
Modem Detect
Command
Command sent to the modem on power up or reset to try to
detect the presence of the phone modem. The modem is
expected to answer “OK”.
Modem Initialization
String
This string is used to initialize the modem before a
telephone number is dialed.
Modem line
See phone line.
Modulo-10000 format
A method used in the MODBUS protocol to spread large
data values across several registers. Each register holds a
value between 0 and 9999. For example, the value
1234567890 would be spread across three separate registers
containing the values 12, 3456, and 7890.
Multiplier
For the Counter, this factor is used in converting the
counter totals into the units selected by the user.
NEMA enclosure
An enclosure that meets National Electrical Manufacturers
Association (NEMA) standards.
Offset
For the Counter, this offset is used in converting the
counter totals into the units selected by the user.
Outbound Address
Offset
Parameter used for store and forward radio
communications.