Pelco CM9760-MXBL Pelco Manual C543M-A (7/03) 49, Logical Numbering

Pelco Manual C543M-A (7/03) 49

It can be difficult and confusing to track large numbers of video input and output

signals in a 9760 system. The “logical number” programming field that exists within

the input/output configuration files of affected devices exists as an aid to minimize

this problem for the programmer as well as for the operator of the system. A logical

number is a user selectable, variable number, and is always associated with an

actual physical input, while physical input numbers, in turn, represent an actual

BNC input on the rear of the matrix bay and each input has a given, fixed number

associated with it. However,

, it is the logical number that is used for reference; therefore, a judicious

choice for logical numbers can help minimize camera/monitor tracking.

Example 1:

As an example of “logical number” use, let’s assume that on each floor of a 5-story

building there exists a camera population ranging from a minimum of 5 to a maximum

of 10 cameras. The camera population might be as follows:

Floor 1: 5 Cameras

Floor 2: 7 Cameras

Floor 3: 10 Cameras

Floor 4: 6 Cameras

Floor 5: 5 Cameras

Can logical numbers be assigned to each of the camera inputs connected to the

matrix bay in the above list a way that would help the operator to track cameras

location?

Let’s assume that logical numbers for the above are assigned according to the

following rules:

(1) Each logical number that references a camera input consists of three digits.

(2) The first digit gives the floor level of the camera location.

(3) The next two digits identify the camera location on the referenced floor accord-

ing to some previously agreed upon sequence.

Looking at floor 4, for example, the physical inputs for the 6 cameras might be

assigned sequential logical numbers 401, 402, 403, 404, 405 and 406; however, if

one wished to allow for future expansion between existing camera locations, the

assigned logical numbers might be assigned with a 5 unit spacing between numbers

and end up with assigned logical numbers of 401, 405, 410, 415, 420, and 425,

respectively. To put a different twist on logical number assignment, let’s assume

that each floor covered a large area, then our “rule three” above might be modified

to let the last two digits represent a division of the floor area into zones; with the

second digit being one of 9 possible zones and the third digit being 1 of 9 possible

cameras within any given zone. The point of all this is, is that there are many and

varied ways to assign logical numbers-it just should be done in a way that makes

sense for your installation.