External Demand Limit Setpoint (Edls) Option; Ecls And Edls Analog Input Signal Wiring Details - Trane CGAM Installation & Operation Manual

Installation - Electrical
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 Service Tool 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 Chilled Water 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).
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
As generated from external source
As processed by 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.

ECLS and EDLS Analog Input Signal Wiring Details:

Both the ECLS 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, the TechView 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 Custom Tab of the
Configuration View within TechView.
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.
86
Voltage Signal
Vdc = 8*(EDLS) + 2
EDLS = (Vdc - 2)/8
Current Signal
mA = 16*(EDLS) + 4
EDLS = (mA - 4)/16
CG-SVX17D-EN