Trane CGAM Installation & Operation Manual page 75

Installation - Electrical
Connect leads from 6K6 to the proper terminals of 1A16.
Refer to the field diagrams which are shipped with the unit.
Silver or gold-plated contacts are recommended.These
customer furnished contacts must be compatible with 24
VDC, 12 mA resistive load.
External Chilled Water Setpoint (ECWS)
Option
The CH530 provides inputs that accept either 4-20 mA or 2-
10 VDC signals to set the external chilled water setpoint
(ECWS).This is not a reset function.The input defines
the set point.This input is primarily used with generic BAS
(building automation systems).The chilled water setpoint
set via the DynaView or through digital communication
withTracer.
The chilled water setpoint may be changed from a remote
location by sending either a 2-10 VDC or 4-20 mA signal to
the 1A14, J2-1 and 2.The 2-10 VDC and 4-20 mA each
correspond to a 10 to 65°F (-12 to 18°C) external chilled
water setpoint.
The following equations apply:
Voltage Signal
VDC =
(8*ECWS + 2*ECWS - 10*ECWS
°F max
Current Signal
mA =
(16*ECWS + 4*ECWS - 20*ECWS
°F max
Note: To convert ECWS values to °F , use the following
formula: °F = 1.8*(°C) + 32
If the ECWS input develops an open or short, the LLID will
report either a very high or very low value back to the main
processor.This will generate an informational diagnostic
and the unit will default to using the Front Panel
(DynaView) Chilled Water Setpoint.
TechView ServiceTool is used to set the input signal type
from the factory default of 2-10 VDC to that of 4-20 mA.
TechView is also used to install or remove the External
ChilledWater Setpoint option as well as a means to enable
and disable ECWS.
External Demand Limit Setpoint (EDLS)
Option
CH530 provide a means to limit the capacity of the chiller
by limiting the number of compressors or stages that are
allowed to run.The maximum number of compressor or
stages allowed to run can vary from one to the number of
stages on the unit.The staging algorithm is free to decide
which compressor or stage shall be turned off or
prevented from running to meet this requirement.
CH530 shall accept either a 2-10 VDC or 4-20 mA analog
input suitable for customer connection to set the unit
external demand limit setpoint (EDLS).
CG-SVX17E-EN
)/(ECWS - ECWS )
min max min
)/ (ECWS - ECWS )
min max min
2-10 VDC and 4-20 mA shall each correspond to an EDLS
range with a minimum of 0% and a maximum of 100%.The
following equations exist.
Global Scroll Voltage Signal
As generated from
Vdc = 8*(EDLS) + 2 mA = 16*(EDLS) + 4
external source
As processed by
EDLS = (Vdc - 2)/8
CH530
The minimum EDLS will be clamped at the front panel
based on 100% /Total number of Compressors. For input
signals beyond the 2-10VDC or 4-20mA range, the end of
range value shall be used. For example, if the customer
inputs 21 mA, the EDLS shall limit it self to the
corresponding 20 mA EDLS.
ECWS and EDLS Analog Input Signal
Wiring Details:
Both the ESWS and EDLS can be connected and setup as
either a 2-10 VDC (factory default), 4-20 mA, or resistance
input (also a form of 4-20 mA) as indicated below.
Depending on the type to be used, theTechView Service
Tool must be used to configure the LLID and the MP for the
proper input type that is being used.This is accomplished
by a setting change on the CustomTab of the
Configuration View withinTechView.
The J2-3 and J2-6 terminal is chassis grounded and
terminal J2-1 and J2-4 can be used to source 12 VDC.The
ECLS uses terminals J2-2 and J2-3. EDLS uses terminals
J2-5 and J2-6. Both inputs are only compatible with
high-side current sources.
Figure 67. Wiring Examples for ECLS and EDLS
Current Signal
EDLS = (mA - 4)/16
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