ProSoft Technology MVI56-AFC - Manual (Page 164)

MVI56-AFC Backplane Communication MVI56-AFC ♦ ControlLogix Platform
User Manual Liquid and Gas Flow Computer
Page 164 of 316 ProSoft Technology, Inc.
February 25, 2011
Output Function Blocks (OFB)
The architecture of the Output Block Array provides you with a flexible and
powerful way to interface the process and other data to the AFC module. A
number of pre-defined Output Function Blocks are at your disposal to implement
as required. Each Output Function Block type carries out a specific function. For
example, the Meter Process Variable Output Function Block transfers the
process variables (temperature, pressure, meter pulses, and so on) to a specific
target meter channel in the AFC module. The calculated flow rates, product
accumulators, and so on are returned to the controller by the AFC in the
associated Input Function Block (IFB) as part of the Input Block Array (IBA). In
the same way a Wall Clock Function Block allows you to synchronize the AFC
Wall Clock to the processor Wall Clock. Like Lego blocks of various sizes, these
function blocks can be stacked together in the data portion of the Output Block
Array as shown in the following diagram:
Element # Attribute
0 Sentinel (Transaction Number)
1 Output Block Length (OBL<=245)
2
Global
Wall Clock
Function Block: 7
Elements
3
Meter 2
Process Variable
Function Block:
12 Elements
. Space for User Allocated Function Blocks
Meter 3
Process Variable
Function Block:
12 Elements
. (Total Available Elements = 245)
Meter 3
Analysis
Function Block:
25 Elements
57
.
.
244
245
246
247 Anchor (Transaction Number)