| Controls 20 - 60 Tons
Interface Standard Control
Features
Human Interface (HI) Panel
The Human Interface (HI) Panel
provides a 2 line X 40 character clear English language liquid crystal display and a 16 button keypad for monitoring,
setting, editing and controlling. The Human Interface
Panel is mounted in the unit’s main control panel and is accessible through
a hatch built into the unit’s control panel door.
The optional remote-mounted version
of the Human Interface panel has all the functions of the unit-mounted HI, with the
exception of the Service Mode. To use a Remote Human
Interface (RHI), the unit must be equipped with an optional InterProcessor
Communications Bridge (IPCB). The RHI can be located up to 5,000 feet from the unit. A single RHI can be used to monitor and
control up to 4 chillers, each containing an IPCB.
The Main Menu of the Human Interface panel:
- STATUS — used to monitor
all temperatures, pressures, setpoints, input and output status. The CUSTOM KEY will have four reports that can be user
defined. The report screens consist of the data
available in the main status menu.
- SETPOINTS — used to edit
all factory preset default setpoints and assign setpoint sources.
- DIAGNOSTICS — used to
review active and historical lists of diagnostic
conditions. A total of 41 different diagnostics can be read at the Human Interface
Panel. The last 20 diagnostics can be held in an active
history buffer log at the Human Interface Panel.
- SETUP — Control
parameters, sensor selections, setpoint source
selections, output definitions, and numerous other points can be edited from this menu. All points have factory preset values so
unnecessary editing is kept to a minimum.
- CONFIGURATION — Preset
with the proper configuration for the unit as it ships from the factory, this information would be edited only if certain
features were physically added or deleted from the
unit. Forexample, if a field supplied Trane Communication
Interface (TCI) module was added to the unit in the
field, the unit configuration would need to be edited to reflect that feature.
- SERVICE — used to
selectively control outputs (for compressors, fans, etc.) when servicing or troubleshooting
the unit. This menu is accessible only at the
unit-mounted Human Interface Panel.
STOP, AUTO — when the chiller is in the stop mode, pressing the AUTO KEY will cause the UCM to go into either
the Auto/Local or Auto/ICS mode, depending on the
setpoint source setting.
Chiller Capacity Control —
The Unit Control Module (UCM) will control leaving solution temperature to a user adjustable setpoint. The UCM monitors the
leaving solution temperature sensor and determines
how far away this temperature is from the leaving solution setpoint and how long it has been there. The rate at which
capacity stages are added or subtracted is determined
by a control integrator algorithm. This algorithm
calculates a control integrator value based upon the inputs from the control
response setpoint, the difference between the leaving
solution setpoint and the leaving solution temperature, the number of capacity
steps, and the design delta temperature. This function
can be user defined for comfort or process control applications. The following setpoints are integrated into the capacity
control algorithm:
Leaving Solution Setpoint (LSS) —
The LSS is adjustable from the factory as standard within a range from 40- 50 °F. Three other possible ranges can be selected and ordered from the factory, 20-29, 30-39°, and 51-65 °F. When these options are selected, the unit hardware changes to allow the unit to
operate under safe conditions.
Design Delta Temperature setpoint
—- the design delta T drop within the evaporator is adjustable from 4-20 °F in one degree increments. In addition, the
control response setpoint can affect the speed of the |
