8
Temperature Reset (4 to 20 mA) —
A field sup-
plied and generated, externally powered 4 to 20 mA signal can
be used to provide leaving fluid temperature reset. The signal
must be connected to TB6. Connect the signal to TB6-2/5
(positive/negative). This is a simple linear function which re-
quires only two configuration changes. Follow the steps out-
lined in Table 2 to enable the function and configure the reset
temperature at 10º F for the 20 mA signal.
The configuration is now complete. As an example, if the
cooling set point (CSP.1) is set to 44 F, the control will linearly
reset the control point (CTPT) based on the 4 to 20 mA signal.
There will be no reset for a 4 mA signal. If the reset signal was
20 mA, the CTPT would be changed to 54 F. Similarly, a
12 mA reset signal would reset CTPT to 49 F. The actual 4 to
20 mA reset signal seen by the control can be viewed by ac-
cessing the item RSET, located under the Inputs mode, sub-
mode 4-20.
Table 2 — Menu Configuration of Temperature Reset Mode
MODE
(RED LED)
KEYPAD
ENTRY
SUBMODE
KEYPAD
ENTRY
ITEM DISPLAY ITEM EXPANSION COMMENTS
CONFIGURATION
DISP
UNIT
OPT1
OPT2
RSET CRST 0
COOLING
RESET TYPE
0 SCROLLING STOPS
0 FLASHING ‘0’
1 SELECT ‘1’
1 CHANGE ACCEPTED
CRST 1
COOLING
RESET TYPE
ITEM/VALUE/UNITS
SCROLLING RETURNS
CRT1 125
CRT2 0
DGRC 0
DEGREES
COOL RESET
SET MAXIMUM
RESET AMOUNT
FOR 20 mA SIGNAL
0 SCROLLING STOPS
0 FLASHING ‘0’
10 SELECT ‘10’
10 CHANGE ACCEPTED
DGRC 10
ITEM/VALUE/UNITS
SCROLLING RETURNS
ENTER
ENTER
ENTER
ENTER
ENTER
ESCAPE
ENTER
ENTER
ENTER
ESCAPE
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