Carrier 040-420 - Manual (Page 42)

P O I N T NUMBER OF
FIRST
CHANNEL
LIMIT
C O D E 3 1 2
4
P W R
I
(ALARM
(MODE
RET
c DO+
D
LEGEND
C O M M Communications Bus
PWR P o w e r
SW Switch
N O T E : F o r s p e c i f i c c o n n e c t i o n p o i n t s ,
see Fig. 24 29.
Fig 6 4 IN/4 OUT Options Module Wiring for Reset, Demand Limit, Dual Set Point
Table 11 Service Functions
To view and modify configurations, the password must
be entered under the log on subfunction.
I
K E Y F A D
F U N C T I O N E N T R Y
DISPLAY COMMENT
P A S S W O R D
Enter Password/
Disable Password
LOGGED ON Logged On
NOTE: Configurations may be modified at this time. When
finished viewing and/or modifying configurations, log out
as follows:
L O G G E D O N
L O G O F F
LOG
V E R S I O N
x x x x x x x x
X
Disable Password
Protection
Logged Off/
Enable Password
Protection
Software
Information
Version No
of Software
Language Options
To use Demand Limit, first enable loadshed, then enter
demand limit set points. See Example 7A. Closing the first
stage demand limit contact puts unit on the first demand
limit level, that is, the unit does not exceed the percentage
of capacity entered as demand limit stage 1. Closing con-
tacts on second-stage demand limit relay prevents unit from
exceeding capacity entered as demand limit stage 2. The
demand limit stage that is set to the lowest demand takes
priority if both demand limit inputs are closed.
The demand limit function must be enabled in order to
function and may be turned off when its operation is not
desired. The demand limit relays can, in off condition, re-
main connected without affecting machine operation.
-Demand Limit, 4-20 Signal The controls can also
accept a 4-20 signal for load shedding. Input for the
signal are terminals shown below:
Externally powered (loop isolator required)
Positive lead to 4 In/4 Out Module
Negative lead to 4 In/4 Out Module
Internally powered
Positive lead to 4 In/4 Out Module
Negative lead to 4 In/4 Out Module
See Field Wiring section on page 71 and Fig. 6.
At field configuration step, select 4-20 by
entering
q
when the LSTYP 0 display appears. See
Example 7B. Then enter set points as follows. In this ex-
ample, set points are coordinates of the demand limit curve
shown in Fig. 8.
42