WattMaster WCC II - Manual (Page 103)

Section 3: Screen Descriptions
WCC II Operator’s Guide
Operator Interfaces 3-71
Divisor: 1
Due to memory limitations within the ECC/WCC II system, the
maximum value of any global analog is 65,535, and the largest
number which can be displayed on the screen is 9999. The value
of the global analog is divided by this number to lower the number
shown on the screen. The maximum divisor allowed is 9999.
i = n
Global value = (
Σ
Di / n) / divisor
i = 1
This is simply the form of the math equation used to generate the
value of this global analog.
If sampling data is unavailable, use 50 as the default value.
If the input value is not available or is invalid, the value of this
global analog will default to this number.
Range
The system has the capability of generating an alarm if the value
of this global analog is either inside or outside of the desired range.
If inside is selected, an alarm will be generated when the value of
the global analog is within the two limits specifi ed. If outside is
selected, an alarm will be generated if the value of the global is
outside the limits specifi ed.
Low Limit High limit
The Low and High Limits can be either an Address or a Value.
When you move the cursor to this fi eld, the word Address or Value
will appear. Since this is a choice fi eld, press the
until the desired choice appears and then press .
If you select Value as the choice for this fi eld, you can enter a
number which will serve as the alarm limit.
If you select Address, you can specify an address such as an analog
input or global analog to be used as the alarm limit.
Press to reset data.
After you enter data on this screen, or after you make any changes
to the screen, you should reset the data by moving the cursor to the
home position on this screen and pressing
and then ,
holding both keys down at the same time for an instant and then
releasing both keys. The computer will beep three times after it has
reset the data. You may also use the reset feature whenever you
want to cause the calculation process to start over.
ANALOG GLOBAL - INTEGRAL
ACCUMULATION MODE
The integral mode may also be used to add data readings together
to obtain an accumulated total. For example, assume that the ECC/
WCC II system is monitoring the gallons per minute (gpm) of
fuel oil used by a building. We can use the integral mode to take
a sample gpm reading every minute and accumulate the readings
to obtain a total gallons used each day. For example, consider the
following table of data:
Time
(minutes since
midnight)
Sample Reading
(gpm)
Value of the
Global Analog
(total gallons)
1 5 5
2 6 11
3 5 16
4 4 20
1439 5 7200
At the end of the day, the total gallons used (7200 in the above
example) can be automatically written on a Trend Log Screen.
After the value is saved on a Trend Log Screen, the total gallons
used can be reset to 0 to allow the system to start accumulating the
next day’s oil usage.
The screen on the next page is a Global Analog Screen using the
accumulation mode to total the gallons of fuel oil used:
Notes: