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FORM 201.23-NM2
ISSUE DATE: 09/25/2020
through 20 mA input (OPTIONS key) and Chiller Con-
trol Board jumper JP5 placed in the "mA" position.
SOUND LIMIT CONTROL
(Local and Remote Reset Control)
Sound Limiting and Local Sound Limit
Setpoint
Sound limit control to reduce overall chiller noise lev-
els at specified times of the day is accomplished by set-
ting a Sound Limit Setpoint. There are several ways to
set the Sound Limit Setpoint. The first is by changing
the Local Sound Limit Setpoint under the PROGRAM
key. This is the value the unit will use for sound limit-
ing, if neither of the other methods is active. If any
other sound limit methods are active, the lowest value
will be used. A sound limit of 0% will allow the unit to
run up to the unit's maximum frequency. A sound limit
of 100% will not allow the unit to run above the mini-
mum frequency. All other sound limit values are linear
between these 2 points.
A sound limit schedule must be programmed under the
SCHEDULE key when sound limiting is utilized. The
schedule defines the time period that sound limiting
will be active.
Sound Limiting is only possible if the option is enabled
by both the OPTIONS key selection and the factory
programmable password protected Unit Setup Mode.
If Sound Limiting is disabled under the
Unit Setup Mode, nothing relating to
Sound Limiting will show up on any dis-
play screen or printout.
ISN Sound Limit Setpoint
The ISN Sound Limit Setpoint can be set via the ISN
II comms. The control panel will only accept a Sound
Limit Setpoint from the ISN if the control panel is in
Remote Control Mode. If the control panel is in Local
Control Mode, the ISN setpoint will be ignored. The
minimum and maximum allowable values will be the
same as the minimum and maximum allowable values
for the Sound Limit Setpoint under the PROGRAM
key. If these values are exceeded, the minimum or
maximum value will be used.
Contact a local Johnson Controls ISN Representative
for details on ISN controls and capabilities.
JOHNSON CONTROLS
Remote Sound Limit
The Sound Limit Setpoint can be set via the Remote
Sound Limit analog input. A zero signal input (0% input)
equates to the minimum sound limit setpoint as defined
under the PROGRAM key Sound Limit Setpoint. A full
scale signal input (100% input) equates to the maximum
sound limit setpoint as defined under the PROGRAM
key Sound Limit Setpoint. The input is linear and may
be adjusted between 0% (minimum sound limiting) and
100% (maximum sound limiting) points.
This input may be used either in Local or Remote Con-
trol Mode. The input will be ignored if the Remote
Sound Limit is disabled under the OPTIONS key. Once
a change to the input is registered, a timer is set to the
value of the Remote Inputs Service Time as program-
mable under the Unit Setup Mode at the factory for the
default value of 15 minutes. The low limit is 5 minutes
and the high limit is 60 minutes. The Remote input will
be ignored until this timer expires. The timer assures
that rapid changes in a remote reset signal don't result
in poor temperature control and excessive compressor
cycling. In most instances, this timer will not need to
be changed, since reset more often than 15 minutes
will create problems with chilled liquid temperature
control. Factory Service should be contacted if a timer
change is required.
Control board jumper JP6 must be positioned correctly
to receive either a voltage (0 VDC to10 VDC or 2 VDC
to 10 VDC) or current (0 mA to 20 mA or 4 mA to 20
mA) signal. Place the jumper in the "V" position for a
voltage signal or mA for a current signal (See Figure
27 on page 166 and Figure 28 on page 167). The
software must be configured under the OPTIONS key
for the type of input signal to be used.
The maximum sound limit is achieved at either 10
VDC or 20 mA. Sending the minimum signal (0 VDC,
2 VDC, 0 mA, or 4 mA based on the OPTIONS key
setting) causes the sound limit to be set to its minimum
(no limiting) value.
0 VDC through 10 VDC Reset Input
A 0 VDC signal produces a 0% sound limit (no change
to max VSD freq). A 10 VDC signal produces a 100%
sound limit (max VSD freq equals min VSD freq). The
sound limit is ramped linearly between these limits as
the input varies between 0 VDC and 10 VDC. In order
for this input to work properly, the Remote Sound Lim-
it must be programmed for 0 VDC through 10 VDC in-
put (OPTIONS key) and Chiller Control Board jumper
JP6 placed in the "V" position.
SECTION 7 - OPERATION
217
7
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