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

 

 

 

43

Page 43
Image 43
Carrier 30GN040-420 operating instructions To Disable Demand Limit, Example 8 Ð Setting Time of Day Day of Week

30GN040-420 specifications

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