Multi-Tech Systems 7500 - Manual (Page 105)

ION 7500 / ION 7600 User’s Guide Basics of ION Architecture
Chapter 4 - Using ION Software Page 105
Sequence of ION Module Execution
ION modules always execute in the order of the data flow (in the example below,
from 1 to 4). This logical execution order is maintained even if you created the
framework from back to front.
ION modules may execute simultaneously if they do not depend on each other for
data (such as both ION modules labelled 1). Conversely, ION module 3 will not
execute until both ION modules 1 and ION module 2 have executed.
ION Registers
Each module has one or more output registers, and most modules have Setup
registers. (A module’s inputs are links to the output registers on other modules.)
There are different types of registers, each classified by the type of data they accept.
When you want to change a module’s configuration, you must supply the type of
data that is appropriate for the register you are configuring. The configuration
tools prevent you from entering the wrong type of data into a register, but they do
not prevent you from entering the wrong value.
The ‘N OT A VAILABLE ’ Value
An ION module that requires a link to one or more of its inputs, but has no such
links created, does not contain any values in its output registers. Instead, its output
registers are set to N
OT A VAILABLE . In addition, if a module has an input that is
invalid (for example, a line-to-neutral measurement for a 3-wire Delta system) its
output register is also set to N
OT A VAILABLE . The N OT A VAILABLE value helps to
distinguish between cases where a register contains a value like 0 or OFF , and cases
where there is actually no value stored.
N OTE
The N OT A VAILABLE value appears in Vista objects that are linked to ION modules with output registers
that are N OT A VAILABLE . The front panel of the meter displays values that are N OT A VAILABLE as dashes (–).
If the inputs of a module are N OT A VAILABLE , its output registers are also N OT
A VAILABLE . The N OT A VAILABLE value propagates through all linked modules.
(The N OT A VAILABLE value propagates through linked Arithmetic modules
differently - refer to the ION Arithmetic module description in the online
ION Programmer’s Reference.)
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1 2
3 4