P, q – Emerson ROC827 User Manual
Page 131
ROC827 Instruction Manual
Issued Mar-06
Glossary
A-5
M
m
Meter.
mA
Milliamp(s); one thousandth of an ampere.
MAC Address
Media Access Control Address; a hardware address that uniquely identifies each node of
a network.
Manual mode
For a ROC, indicates that the I/O scanning has been disabled.
MAU
Medium Attachment Unit.
MCU
Master Controller Unit.
Modbus
A popular device communications protocol developed by Gould-Modicon.
MPU
Micro-Processor Unit.
mm
Millimeter.
MMBTU
Million British Thermal Units.
msec
Millisecond, or 0.001 second.
MVS
Multi-Variable Sensor. A device that provides differential pressure, static pressure, and
temperature inputs to a ROC for orifice flow calculations.
mV
Millivolts, or 0.001 volt.
mW
Milliwatts, or 0.001 watt.
N
NEC
National Electrical Code.
NEMA
National Electrical Manufacturer’s Association. See http://www.nema.org.
O
OH
Off-Hook modem communications signal.
Off-line
Accomplished while the target device is not connected (by a communications link). For
example, “off-line configuration” refers to configuring an electronic file that is later loaded
into a ROC.
Ohms
Units of electrical resistance.
On-line
Accomplished while connected (by a communications link) to the target device. For
example, “on-line configuration” refers to configuring a ROC800-Series unit while
connected to it, so that you can view the current parameter values and immediately load
new values.
Opcode
Type of message protocol the ROC uses to communicate with the configuration software,
as well as host computers with ROC driver software.
Operator
Interface
Also LOI or Local Port; the serial EIA-232 (RS-232) port on the ROC through which local
communications are established, typically for configuration software running on a PC.
Orifice meter
A meter that records the flow rate of gas through a pipeline. The flow rate is calculated
from the pressure differential created by the fluid passing through an orifice of a particular
size and other parameters.
P, Q
Parameter
A property of a point that typically can be configured or set. For example, the Point Tag
ID is a parameter of an Analog Input point. Parameters are normally edited by using
configuration software running on a PC.
PC
Personal Computer.
Pf
Flowing pressure.