Avs And Bvs; Ddc Execution And Status - Honeywell ALERTON ACM-VLX Installation And Operation Manual

Installation and Operations Guide

AVs and BVs

DDC execution and status

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ACM-VLX/VLX/EXP/AXM
Priority-array index 4 reflects H-O-A status:
• 0 = Switch in OFF position
• 0-100 = Switch in HAND position and potentiometer at 0 (min.) to 100
(max.) of tuning range
• NULL = Switch in AUTO position
The H-O-A switch overrides all software commands, regardless
IM POR TANT
of the command's priority for writing. If a command is written at priority-array
index 1, 2, or 3, and the H-O-A switch is in HAND or OFF mode, the present-
value may not accurately reflect the actual status of the output.
AVs and BVs in the 0–7999 range are reserved for special uses as explained
throughout this guide (for example, input configuration and H-O-A status). AVs
and BVs available for general use in programming and automation are in the
range 8000-8499.
General purpose AVs and BVs in the VLX/ACM-VLX have a priority-array
property that governs their present-value. Configuration AVs and BVs do not.
See Table 13 on page 60 to identify the priority for writing to the present-value
that specific automation features use.
DDC execution time depends on the size and complexity of DDC. Typically,
DDC execution time does not exceed 500 mS. If DDC execution time and size
are a concern, use the Alerton Diagnostics (513) property of the Program 1024
object in the VLX/ACM-VLX to monitor DDC execution time and the amount
of memory occupied by DDC.
This is a proprietary Alerton property. Place a read-only item referencing this
property on a data display or device template.
This property is now available on the Alerton\Standard templates.
Note
Fig ure 25 Placing the Ale rton Diagnos tics (513) prope rty of the Program 1024
obje ct on a de vice te mplate for a VLX/ACM-VLX with de vice ins tance 211
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