Edls And Ecws Analog Input Signal Wiring Details; Chilled Water Reset (Cwr) - Trane Tracer TD7 User Manual

The following equations apply for EDLS:
Voltage Signal
As generated from VDC+0.133*(%)-6.0
external source
As processed by %=7.5*(VDC)+45.0
UCM
If the EDLS input develops an open or short, the LLID
will report either a very high or very low value back to
the man processor. This will generate an informational
diagnostic and the unit will default to using the Front
Panel (Tracer TD7) Current Limit Setpoint.
The Tracer™ TU Service Tool must be used to set the
input signal type from the factory default of 2-10 VDC to
that of 4-20 mA current. Tracer TU must be also be used
to install or remove the External Demand Limit Setpoint
Option for fi eld installation, or can be used to enable or
disable the feature (if installed).
EDLS and ECWS Analog Input
Signal Wiring Details:
Both the ECWS 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 4-2OmA) as indicated
below. Depending on the type to be used, the Tracer TU
Service Tool must be used to confi gure 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 Confi guration View within Tracer TU.
Important: : For proper unit operation, BOTH the EDLS
and ECWS settings MUST be the same
(2-10 VDC or 4-20mA), even if only one
input is to be used.
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. ECWS uses
terminals J2-5 and J2-6. Both inputs are only compatible
with high-side current sources.
Figure 2. Wiring examples for EDLS and ECWS
2-10 VDC, 4-20mA
Resister
I = 20/(R + 200)
RLC-SVU006A-E4
Current Signal
mA=0.266*(%)-12.0
%=3.75*(mA)+45.0
J2-1 & 4 Dual
J2-2 & 5 Analog
J2-3 & 6 I/O LLID
J2-1 & 4 Dual
J2-2 & 5 Analog
I
J2-3 & 6 I/O LLID
J2-1 & 4 Dual
J2-2 & 5 Analog
J2-3 & 6 I/O LLID
Installation Electrical

Chilled Water Reset (CWR)

UC800 resets the chilled water temperature set point
based on either return water temperature, or outdoor air
temperature. Return Reset is standard, Outdoor Reset is
optional.
The following shall be selectable:
• One of three Reset Types: None, Return Water
Temperature Reset, Outdoor Air Temperature Reset, or
Constant Return Water Temperature Reset.
• Reset Ratio Set Points.
For outdoor air temperature reset there shall be both
positive and negative reset ratio's.
• Start Reset Set Points.
• Maximum Reset Set Points.
The equations for each type of reset are as follows:
Return
CWS' = CWS + RATIO (START RESET - (TWE - TWL))
and CWS' > or = CWS
and CWS' - CWS < or = Maximum Reset
Outdoor
CWS' = CWS + RATIO * (START RESET - TOD)
and CWS' > or = CWS
and CWS' - CWS < or = Maximum Reset
where
CWS' is the new chilled water set point or the "reset
CWS"
CWS is the active chilled water set point before any reset
has occurred, e.g. normally Front Panel, Tracer, or ECWS
RESET RATIO is a user adjustable gain
START RESET is a user adjustable reference
TOD is the outdoor temperature
TWE is entering evap. water temperature
TWL is leaving evap. water temperature
MAXIMUM RESET is a user adjustable limit providing
the maximum amount of reset. For all types of reset,
CWS' - CWS < or = Maximum Reset.
Range
Reset Reset Start
Type Ratio Reset
10 to
Return 4 to 30 F 0 to 20 F 1%
120%
(2.2 to
16.7 C)
80 to 50 to
Outdoor
-80% 130 F
(10 to
54.4 C)
Increment
Max
IP Units SI Units
Reset
1%
(0.0 to
11.1 C)
0 to 20 F 1% 1%
(0.0 to
11.1 C)
Factory
Default
50%
10%
11