Application

Sequence of Operation
Venturi Table Evaluation and Editing (Mode 1, 3)
24
Siemens Industry, Inc.
BACnet LCM-OAVS, Application 6754
140-1325
2015-07-07
NOTES:
1. If
SUP FLO COEF is 0, the table edit feature uses a supply flow coefficient of 1.
2. If
SUPDUCT AREA is 0, the table edit feature uses a supply duct area of 1 square
foot.
3. If
GEX FLO COEF is 0, the table edit feature uses a general exhaust flow
coefficient of 1.
4. If
GEXDUCT AREA is 0, the table edit feature uses a general exhaust duct area of
1 square foot.
The following table lists all values for V TABLE PT and describes their use. Any range
of points not specifically mentioned (such as 47 through 60) is unused.
Venturi Air Valve Table Statement
V TABLE PT
Description
0
Default value for V TABLE PT. When V TABLE PT equals 0, changes to
TABLE FLOW or TABLE VOLTS are ignored. Setting V TABLE PT to 0
cancels an edit session.
Active
Exhaust
31
Setting V TABLE PT to 31 takes the flow (cfm) and voltage values from
the first element of the active exhaust table and displays them in
TABLE
FLOW and TABLE VOLTS where they can be edited. (This is the only
active exhaust element (or “point”) that can be directly edited.) Flow and
voltage values are not allowed to exceed those in active exhaust point 32.
To operate in the range below minimum readable flow (less than 350
fpm), a low flow value in cfm from either the room schedule or the
general-exhaust Venturi Air Valve housing is entered into
TABLE FLOW,
with the correct corresponding actuator voltage determined/confirmed by
the balancer and entered into
TABLE VOLTS.
NOTE: This point is only necessary for general-exhaust Venturi Air Valve
operation in the range below minimum readable flow (below 350 fpm).
Otherwise it can be ignored. This low flow point must be entered only
after other non-zero points exist in the table as a result of manual edits, or
as the result of a prior Venturi auto calibration sequence.
32 - 46
This portion of the table (32 through 46) can be viewed but not edited
directly. When a point is selected (that is, when
V TABLE PT is set to a
value 32 through 46), the corresponding flow and voltage values are
displayed in
TABLE FLOW and TABLE VOLTS.
Setting
V TABLE PT to 32 will result in the smallest readable flow and
associated voltage for the exhaust Venturi Air Valve to be displayed in
TABLE FLOW and TABLE VOLTS. Setting V TABLE PT to 46 will result
in the maximum flow and associated voltage for the exhaust Venturi Air
Valve to be displayed in
TABLE FLOW and TABLE VOLTS. The in
between values (33 through 45) are for the range of flow between min
and max.
NOTE: The table swap will fail if valid flow and voltage values are not
entered in Point 46.
Table entries marked as failed display FAIL for both flow and voltage.
Inactive
Exhaust
91 – 106
This portion of the table can be viewed and edited. By entering a point
(any value 91 through 106) into
V TABLE PT, the corresponding cfm and
voltage values display in
TABLE FLOW and TABLE VOLTS where they
can be edited.
Exhaust
Swap
121
Setting V TABLE PT to 121 instructs the controller to evaluate the values
in the inactive exhaust portion of the table using standard calibration
pass/fail logic. If they pass, they are exchanged with those in the active
exhaust portion of the table.