Carrier 30GN040-420 To Disable Demand Limit, Example 7B Ð Using Demand Limit 4-20mA

At ®eld con®guration step, select 4 to 20 mA loadshed

by entering (internally powered) or (externally pow-

ered) when the LSTYP 0 display appears. See Example 7B. Then enter set points as follows. In this example, set points are coordinates of the demand limit curve shown in Fig. 9.

Example 7A Ð Using Demand Limit (First Log On as Shown in Table 12)

KEYPAD	DISPLAY	COMMENTS
ENTRY	RESPONSE
	FLD CFG	Field con®guration sub-
		function of service function
	LSTYP 0	Loadshed is not enabled
	LSTYP 1	Loadshed is now enabled
		for 2-stage switch control
		Demand Limit set points
	DEMAND	subfunction of set point
		function
	DLS1 80	Loadshed 1 currently set
		at 80%
	DLS1 60	Loadshed reset to 60%
	DLS2 50	Loadshed 2 currently set
		at 50%
	DLS2 40	Loadshed 2 reset to 40%

To Disable Demand Limit:

KEYPAD	DISPLAY	COMMENTS
ENTRY	RESPONSE
	FLD CFG	Field con®guration sub-
		function of service function
	ERTYP 0	Scroll past other elements
		in the subfunction
	LSTYP 1	Loadshed is enabled for
		2-stage switch control
	LSTYP 0	Loadshed is now disabled

NOTES:

1.Select 2 for internally powered 4 to 20 mA signal load limiting.

2.Select 3 for Carrier Comfort Network loadshed.

3.Select 4 for externally powered 4 to 20 mA signal load limiting.

Example 7B Ð Using Demand Limit (4-20 mA)

(First Log On As Shown in Table 12)

KEYPAD	DISPLAY	COMMENTS
ENTRY	RESPONSE
	FLD CFG	Field con®guration subfunction
		of service function
	ERTYP 0	Scroll past other elements in
		the subfunction
	LSTYP 0	Loadshed is not enabled
		Loadshed is now enabled
	LSTYP 2	for 4-20 mA internally-powered
		signal control
	DEMAND	Demand Limit set points
	DL20 100	Maximum demand limit is 100%
	DL20 90	Maximum demand limit is 90%

Scrolling past the 4 to 20 mA demand limit set point brings up the loadshed set points. The loadshed feature is activated by a redline alert and loadshed commands from the CCN loadshed option. The ®rst set point is the group number, es- tablished by the CCN system designer. The second option is

the loadshed demand delta, which de®nes the percent of the load to be removed when a loadshed command is in effect. The third set point is maximum loadshed time, which de- ®nes the maximum length of time that a loadshed condition is allowed to exist. The allowable range for this entry is zero to 120 minutes.

Subfunction displays date, time, and day of the week.

Reading and Changing Time Display Ð Time is entered and displayed in 24-hour time. The day of the week is entered as a number.

1 = Mon, 2 = Tue, 7 = Sun, etc.

Key is used as the colon when entering time. See Example 8.

subfunction accesses the leaving chiller ¯uid alert

limit (LMT) option. The value to be entered here is the num- ber of degrees above the control set point at which an alert should be generated. For example, if the control set point is 44 F, and an alert is desired (alert 70) if the ¯uid temperature reaches 50 F, then enter 6 for this set point. The allowable range for this entry is between 2 and 30 (F).

SERVICE FUNCTION Ð This function allows the techni- cian to view and input con®guration data. Factory con®gu- ration data, ®eld con®guration data, and service con®gura- tion data may be viewed or entered through the keypad and display module. See Table 9 for a complete listing of con- ®gurable items. Whenever a processor module is replaced in the ®eld, the complete list of con®guration codes must be entered.

Logging On/Logging Off Ð The service function is pass- word protected. Therefore, to gain entry to this function,

this password must be entered. Pressing

allows the technician to view, change, or enter con®guration codes. To log off, perform the following keystrokes:

. The service function is once again password protected.

Software Information Ð displays the version

number of the software that resides in the processor

module. The and subfunctions are summa- rized in Table 12.

Example 8 Ð Setting Time of Day and

Day of Week

KEYPAD	DISPLAY	COMMENTS
ENTRY	RESPONSE
		Time display sub-
	TIME	function of set point
		function
	MON 16.00	Current setting is
		Monday, 4:00 p.m.
		New setting of
	TUE 13.05	Tuesday, 1:05 p.m.
		is entered
		and displayed
	JAN 01 90	Current date is
		Jan. 1, 1990
		New setting
	APR 15 90	April 15, 1990
		is entered
		and displayed

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