22
YORK INTERNATIONAL
INTRODUCTION
The YORK MicroComputer Control Center is a micro-
processor based control system capable of multi-circuit
control to maintain chilled liquid temperature.
A 40 character display (2 lines of 20 characters) allows
the operator to display system operating parameters as
well as access programmed information already in
memory. A keypad for programming and accessing
setpoints, pressures, temperatures, motor current, cut-
outs, daily schedule, options, and fault information is
provided.
A master ON/OFF switch is available to activate or
de-activate the chiller system. Separate system (SYS)
switches for each refrigerant system (up to 4) are pro-
vided on the Microprocessor Board.
Remote cycling, unloading, and chilled water tempera-
ture reset can be accomplished by user supplied dry
contacts.
Compressor starting/stopping and loading/unloading de-
cisions are performed by the Microprocessor to maintain
leaving water temperatures. These decisions are a func-
tion of temperature deviation from setpoint and rate of
change of temperature.
MICROPROCESSOR BOARD
The Microprocessor Board is the controller and decision
maker in the control panel. System inputs from pressure
transducers, temperature sensors, and C.T.s are con-
nected directly to the Microprocessor Board. The Micro-
processor Board circuitry multiplexer these analog in-
puts, digitizes them, and constantly scans them to keep
a constant watch on the chiller operating conditions.
From this information, the Microprocessor then issues
commands to the Relay Output Board to control
contactors, solenoids, etc. for water temperature control
and to react to safety conditions.
Keypad commands are acted upon by the micro to
change setpoints, cut-outs, scheduling, operating re-
quirements, and to provide displays.
26572A(D)
UNIT CONTROLS AND OPERATION
YORK MICROCOMPUTER CONTROL CENTER
FIG. 8
MICROCOMPUTER CONTROL CENTER
Summary of Contents for YCAJ44HE8
Page 16: ...16 YORK INTERNATIONAL WIRING DIAGRAMS LD02165 FIG 5 ELEMENTARY DIAGRAM...
Page 17: ...FORM 150 60 NM3 17 YORK INTERNATIONAL FIG 5 ELEMENTARY DIAGRAM Cont d LD02166...
Page 20: ...20 YORK INTERNATIONAL CONNECTION DIAGRAM ELECTRICAL BOX FIG 7 CONNECTION DIAGRAM LD02171...
Page 21: ...FORM 150 60 NM3 21 YORK INTERNATIONAL FIG 7 CONNECTION DIAGRAM Cont d LD02172...