Daikin AWV024 - Circuit Status; Compressor Control; Run Command Output; Cycle Timers

IOM 1242-2 • PATHFINDER
®
MODEL AWV CHILLERS 60 www.DaikinApplied.com
CIrCuIT funCTIons
Circuit Status
Circuit Status is displayed to indicate the general condition of
the circuit. The following table lists the text displayed for each
circuit status and the conditions that enable each status. If
more than one status is enabled at the same time, the highest
numbered status overrides the others and is displayed.
Table 47: Circuit Status
Enum Status Conditions
1 Off:Ready
Circuit is ready to start when
needed
2 Off:Cycle Timer
Circuit is off & cannot start due to
active cycle timer
3 Off:OAT Low
Circuit is off & cannot start due to
low ambient lockout
4
Off: Max Starts
Per Hr
Circuit is off & cannot start due to
exceeding 4 starts/hr
5 Off:BAS Disable
Circuit is off & cannot start due to
BAS Circuit Mode input being set
to Off
6
Off:Keypad
Disable
Circuit is off & cannot start due to
Circuit Mode set point on HMI is
set to Disable
7
Off:Circuit
Switch
Circuit is off & circuit switch is off
8 Off:Oil Heating
Circuit is off & Oil Sump Check =
Not Ready
9 Off:Alarm
Circuit is off & cannot start due to
active circuit alarm
10 Off:Test Mode Circuit is in test mode
11 EXV Preopen Circuit is in preopen state
12 Run:Pumpdown Circuit is in pumpdown state
13 Run:Normal
Circuit is in run state & running
normally
14
Run:Evap Press
Low
Circuit is in start or run state &
cannot load due to low evaporator
pressure
15
Run:Cond Press
High
Circuit is in start or run state &
cannot load due to high condenser
pressure
16
Run:VFD
Current High
Circuit is in start or run state &
cannot load due to high VFD line
current
17
Run:VFD Temp
High
Circuit is in start or run state &
cannot load due to high VFD
temperature
18
Run:Motor
Current High
Circuit is in start or run state &
cannot load due to high motor
current
19
Run:High LWT
Limit
Circuit is in start or run state &
cannot load due to the evaporator
LWT exceeding the limit for
allowing full capacity
Compressor Control
The compressor is controlled via:
• a digital output to give the run command to compressor
VFD
• a modbus speed command to control compressor speed
• digital outputs for compressor VR solenoids to control VR
• a digital output for liquid injection to the compressor
Run Command Output
The compressor run command output should be on when the
circuit state is Start, Run, or Pumpdown. It should be off when
the circuit state is Off or Preopen.
Cycle Timers
A minimum time must pass between starts of each compressor.
When the compressor starts, a timer starts which will run for a
time determined by the Start-Start Timer set point.
A minimum time must pass between the stop and start of each
compressor. When the compressor stops, a timer starts which
will run for a time determined by the Stop-Start Timer set point.
While either timer is running, the compressor cannot start. Both
cycle timers will be enforced even through cycling of power to
the chiller. These timers may be cleared via the Clear Cycle
Timers set point.
Starts Per Hour Limit
In addition to the cycle timers, a limit of four starts per hour
is enforced. A buffer of start times for the last four starts is
maintained. If the current time is an hour or less after the rst
timestamp in the buffer, the next start will be delayed.
This limit is cleared if the Clear Cycle Timers set point is set to
Yes.
Capacity Control
The compressor will vary capacity via changes to the motor
speed (frequency).
Auto Capacity Control
The normal speed change is 1 Hz for all compressor
congurations.
Circuit State = Off - Speed command is 0 Hz.
Circuit State = Preopen - Speed command is set to the
minimum for the conguration.
Circuit State = Start - Immediately after starting, the
compressor speed will be set to the minimum for the
conguration and held there while circuit state is Start.
Circuit State = Run - After the circuit enters the Run state,
changes to the speed are performed based on load and unload
commands coming from the unit capacity control logic (see
unit capacity control section). The speed is constrained to a
range from the minimum based on the conguration up to the
Compressor Maximum Speed set point.