Using H-O-A Switches And Trimpots - Honeywell ALERTON ACM-VLX Installation And Operation Manual

Installation and Operations Guide
Fig ure 27 S tatus LED flas h patte rns in the e ve nt of EXP/AXM communication dis ruption

Using H-O-A switches and trimpots

© Honeywell. All Rights Reserved. LT-VLXEXPAXMIOG Rev. 01
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VLX/ACM-VLX/EXP/AXM operation and maintenance
For each AO and BO terminal on an EXP/AXM, a Hand-Off-Auto (H-O-A)
switch enables manual override of the commanded output status. For AOs, the
H-O-A switch is combined with a trimpot, which drives the output when the
corresponding H-O-A switch is in the H position.
H-O-A switches always override all software commands and backup mode
values.
H-O-A switch status and trimpot values are reported through reserved AVs in the
VLX/ACM-VLX for use in software. See "Appendix G: H-O-A and trimpot
status values" on page 95.
Table 1 6
H-O-A s witch ope ration
S witc h po s itio n BO o pe ratio n
A (de fault) S oftware controlle d
O OFF
H ON
AO o pe ratio n
S oftware controlle d
Off (0%). One -s e cond de lay be twe e n
s witch s e t and output re s pons e to
accommodate trans itions from H to A
through this pos ition.
Trimpot control. Lift the cove r and us e a
s mall s cre wdrive r to adjus t the trimpot
corre s ponding to the output. Fully
counte r-clockwis e = 0% (0 mA or 0
VDC), Fully clockwis e = 100% (20mA or
10 VDC).
65