Honeywell W7750A specifications Approximate Memory Size Estimating Procedure, 109 74-2958

EXCEL 10 W7750A,B,C CONSTANT VOLUME AHU CONTROLLER

Appendix D. Q7750A Excel 10 Zone Manager Point Estimating Guide.

Memory size approximation is shown below: (all sizes in bytes)

When memory size is less than 110,000 bytes, the size is OK.

When memory size is between 110,000 and 128,000 bytes, the application may be too large. The user must expect to reduce the application complexity, reduce the number of attached Excel 10s or distribute the Excel 10s over more than one Zone Manager.

When memory size is greater than 128,000, the size is too large. The application size must be reduced as described above.

Approximate Memory Size Estimating Procedure.

1.Determine the number of points per controller required at the Central (for example, XBS).

NOTE: All remaining points that are not mapped can be accessed through the Direct Access feature.

2.Calculate the number of Excel 10 Zone Manager pro- gram points that are used in control logic and in the switching table.

3.Estimate the program complexity of the Zone Manager (one of three levels).

a.No time programs, control logic, or switching tables.

b.10K of control logic (one time program, five switching tables, and five control loops).

c.20K of control logic (multiple time programs, ten

switching tables, and ten control loops).

Use Fig. 51 to determine the number of Excel 10s that can be connected to the Zone Manager.

NOTE: More than 60 Excel 10s requires a Router.

4.Repeat for each Q7750A Excel 10 Zone Manager in a project.

920

900

800

NUMBER OF 765 C-BUS POINTS (EXCEL 10 MAPPED

POINTS	700
PLUS ZONE
MANAGER
POINTS)

610

600

(A)NO TIME PROGRAM, NO CONTROL LOOPS, NO SWITCHING TABLES.

(B)10K CONTROL PROGRAM (FOR EXAMPLE,

1 TIME PROGRAM,

5 CONTROL LOOPS,

5 SWITCHING TABLES.)

(C)20K CONTROL PROGRAM

(I.E., MULTIPLE TIME PROGRAMS, 10 CONTROL LOOPS,

10 SWITCHING TABLES.)

900

895

800

NUMBER OF

740C-BUS POINTS

(EXCEL 10 MAPPED

700POINTS PLUS ZONE MANAGER POINTS)

600

585

20	60	120
(OR LESS)	(ADD ROUTER)
	NUMBER OF EXCEL 10s	M8729

Fig. 51. Point capacity estimate for Zone Manager.

The exact equation for calculating memory size follows:	Excel 10 units	= number of attached Excel 10s.
Memory size = 21,780	C-Bus points	= including mapped points and others; for
+ 4096 (in case of a time program).		example, remote points.
+ CARE Control Program.	Mapped points = number of mapped points per Excel 10,
+ 14 x time points x Excel 10 units.		including One-to-Many and
+ 50 x Excel 10 units.		Many-to-One mechanism.
+ map complexity x Excel 10 units x mapped points.	Excel 10 types = number of different Excel 10 types
+ 57 x C-Bus points.		(currently three)
+ 7488 x Excel 10 types.	Map complexity=
	20	=using One-to-Many and not using points
Where:		with read/write.
Time points = number of switch points in time program	30	= average.
per Excel 10.	45	= many points with read/write ability.

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