Instruction Manual

Instruction Manual
D103434X012
Glossary
November 2014
190
Gain
The ratio of output change to input change.
Hardware Revision
Revision number of the Fisher instrument
hardware. The physical components of the
instrument are defined as the hardware.
Instrument Serial Number
The serial number assigned to the instrument.
Lower Range Value (LRV)
Lowest value of the process variable that the
digital level controller is currently configured to
measure in the 4 to 20 mA loop.
Lower Sensor Limit (LSL)
Lowest value of the process variable that the
digital level controller can be configured to
measure.
Memory
A type of semiconductor used for storing
programs or data. FIELDVUE instruments use
three types of memory: Random Access Memory
(RAM), Read Only Memory (ROM), and
Non‐Volatile Memory (NVM). See also these
listings in this glossary.
Menu
A list of programs, commands, or other activities
that you select by using the arrow keys to
highlight the item then pressing ENTER, or by
entering the numeric value of the menu item.
Message
Thirty‐two character field for any additional
information the user may want to include.
Multidropping
The connection of several field devices to a single
communications transmission line.
Non‐Volatile Memory (NVM)
A type of semiconductor memory that retains its
contents even though power is disconnected.
NVM contents can be changed during
configuration unlike ROM which can be changed
only at time of instrument manufacture. NVM
stores configuration data.
On‐Line Configuration
Configuration of the digital level controller
operational parameters using a Field
Communicator connected to the instrument.
Parallel
Simultaneous: said of data transmission on two or
more channels at the same time.
Polling Address
Address of the instrument. If the digital level
controller is used in a point‐to‐point
configuration, set the polling address to 0. If it is
used in a multidrop configuration, or split range
application, set the polling address to a value
from 0 to 15.
Process Variable (PV)
A physical quality or quantity which is monitored
as part of a control strategy. The digital level
controller can measure level, interface level
between two liquids of different specific gravity,
and liquid density.
Protocol
A set of data formats and transmission rules for
communication between electronic devices.
Devices that conform to the same protocol can
communicate accurately.
Random Access Memory (RAM)
A type of semiconductor memory that is normally
used by the microprocessor during normal
operation that permits rapid retrieval and storage
of programs and data. See also Read Only
Memory (ROM) and Non‐Volatile Memory (NVM).
Read‐Only Memory (ROM)
A memory in which information is stored at the
time of instrument manufacture. You can
examine but not change ROM contents.