Yaskawa VCD 723 - Manual (Page 110)

Glossary
104 Glossary
9/15/93
difference and the required gains of the regulator. The other segment consists of
the code used to calculate the gains required for the speed regulation function in
the format required by that segment. In other words, it translates from the
engineering terms used to describe regulator performance (such as load inertia
and desired crossover frequency) to the integral and proportional gains required
by the regulator segment. Since these defining parameters are rarely changed,
this segment needs to execute only rarely, thus saving processor time for other
functions which do require frequent execution.
Conditional scan – Conditional scan tasks define sub-programs (i.e. sub-
programs consisting of unique interconnections of PAC tasks) which execute
only when certain logic conditions related to the conditional scan task are
satisfied. When the conditional scan executes, the program defined for the
conditional scan executes at the scan level at which the conditional scan task is
programmed (see SCAN definition). The use of conditional scans allows greater
utilization of the limited processor time.
Custom fault – A fault (or error) defined via the PAC task “FLTD”. These
faults have significance only to a particular PAC design. (See Fault or Error
definition).
D/A – Digital to Analog converter.
DCU – Drive Control Unit. The drive control unit refers to the hardware and
software used to control the drive as opposed to the hardware and software used
to control the power conversion process. Specifically, it refers to the hardware
and software associated with the DCU microprocessor. The DCU software
includes the variable software generated as a result of the PAC program and the
fixed software (see Kernel definition) used to control execution of the PAC
program.
Default menu – A menu for an RDU that contains the default menu items as
received through the LAN from the drives. Each drive connected to the LAN
can have default menu items that are to be displayed on specific RDUs. The
default menu items and the order of the menu items are determined by the PAC
programmer.
Directed message – A type of LAN message which can be received only by one
LAN Node. This type of message contains both the source and destination Node
numbers.
Elemental PAC task – The simpler PAC language functions where everything
associated with that function is contained in one sequentially executed module.
EPROM – Erasable Programmable Read Only Memory. An integrated circuit
that is usually used to hold the instructions for a microprocessor’s program.