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FORM 160.00-O4
ISSUE DATE: 12/19/2017
The compressor's inlet guide vanes, which are used
in fixed speed applications to control the amount of
refrigerant gas flowing through the compressor, are
controlled together with the compressor speed on an
OSCD chiller system to obtain the required chilled liq-
uid temperature while simultaneously requiring mini-
mum power from the AC line.
The ACC board automatically generates its own
"Adaptive" three-dimensional surge surface map while
the chiller system is in operation. This "Adaptive" op-
eration is accomplished through the use of a patented
surge detection algorithm. The novel surge detection
system utilizes pressure information obtained from the
chiller's two pressure transducers or the OSCD's in-
stantaneous power output to determine if the system
is in "surge". Thus the adaptive system permits con-
struction of a customized compressor map for each in-
dividual chiller system. Benefits of this new adaptive
system include: (1) a customized compressor map for
each chiller which eliminates inefficient operation due
to the safety margin built into the previous designs to
compensate for compressor manufacturing tolerances
(2) the ability to update the system's surge surface as
the unit ages and (3) automatic updating of the com-
pressor map if changes in refrigerant are implemented
at a later date.
The Control Center beginning in 2005
A major change in the control system took place in
2005. Several redesigns took place in the OptiView
panel and the OSCD. The redesign replaced micro-
processors that were becoming obsolete. This was a
time to take advantage of new components that were
now available. An additional communications port was
added so that the communications between the mi-
croboard and the OSCD logic board was faster. In the
changes to the microboard the function of the Adaptive
Capacity Board was placed into the microboard, and
the ACC board was longer needed in new production.
The new microboard is also compatible with the older
designs microboards used in the OptiView panel. The
new OSCD logic also added this new communication
port, but also retained all of the functions required to
still communicate with the ACC board.
14
OptiSpeed and Optional Harmonic Filter Logic
Control Boards
Within the enclosure of the VSD model drive, the
OSCD logic board and optional Harmonic Filter log-
ic board are interconnected via a 16-position ribbon
cable. This cable provides power for the Filter logic
board and a method of communications between the
two boards.
The OSCD Logic board performs numerous functions,
control of the OSCD's cooling fans and pumps, when
to pre-charge the bus capacitors, and generates the
PWM.
The OSCD Logic board also determines shutdown
conditions by monitoring the three phases of motor
current, heatsink temperature, baseplate temperature,
internal ambient temperature, and the DC bus voltage.
The optional Harmonic Filter logic board determines
when to precharge the harmonic filter power unit, when
to switch the transistors in the harmonic filter power
unit, and collects data to determine power calculations.
This board also uses this data to determine shutdown
conditions.
Microcomputer Control Panel VSD Related
Keypad Functions
Refer to 160.00-M4 for related keypad functions.
Some of the displayed data in this form is different
from the 160.00-M1. Under the Options Key – the
following changes will be displayed:
VSD PHASE A INVERTER HEATSINK TEMP = ___°F.
VSD PHASE B INVERTER HEATSINK TEMP = ___°F.
VSD PHASE C INVERTER HEATSINK TEMP = ___°F.
These three temperature values are replaced with:
VSD BASEPLATE TEMP = ___°F
For the 270, 292, 351 and 424 Hp drives. The 385, 419,
503, 608, 658, 704 and 900 Hp drives will display 3
phases of Baseplate temperature. When the Filter is
present the following data will change.
FILTER HEATSINK TEMP = ___°F.
This temperature data will now be called.
FILTER BASEPLATE TEMP = ___°F.
JOHNSON CONTROLS
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