ProSoft Technology MVI56-AFC - Manual (Page 165)

MVI56-AFC ♦ ControlLogix Platform MVI56-AFC Backplane Communication
Liquid and Gas Flow Computer User Manual
ProSoft Technology, Inc. Page 165 of 316
February 25, 2011
Input (Transaction) Block Array Definition
The Input Block Array is where the AFC returns the (processed and calculated
data) responses to all function blocks received in the Output Block Array from the
controller. It returns Input Function Blocks in locations and sizes matching those
of the OFBs in the OBA. The AFC completes the actions implied by all function
blocks before responding with the IBA to the controller. If the AFC is unable to
determine the size of any function block, or the implied size overlaps the block
array’s anchor, then that and all following function blocks are not processed and
a format alarm is raised.
The 250 integer elements of the Input (Transaction) Block Array (IBA) that are
returned to the controller to the AFC module are defined as follows:
Element Attribute
0 Sentinel Echo (Transaction Number)
1 Block length echo (IBL) (Negative if formatting error present)
2
3
4 Space for Input Image of User Allocated Function Blocks
. (Total Available Elements = 245)
.
.
.
244
245
246
247 Site Status
Bit # Site Status
0 MVI56-AFC Released and Active
1 Checksum Alarm
2 Reserved
3 Reserved
4 Processor Halted, Offline or Missing
5 Measurement Configuration Changed
6 Set upon Power-Up & cleared when the Wall Clock is set for the first
time
7 Cold Start: remains set until first enabled meter is detected
8 Modbus Master poll pending
9 Modbus Master poll complete, results waiting
10 Pass-Thru input pending
11 version 2.06 or later
12 to 15 Reserved
248 Meter Alarm Map: Bit set=Meter in Alarm
249 Anchor Echo (Transaction Number)
The input block returned by the AFC module has the sentinel echo and the
anchor echo in fixed locations.
Note: The anchor echo is returned as the 250th element in the IBA and not as the 248th element
as sent in the OBA.