Application

Sequence of Operation
Venturi Table Evaluation and Editing (Mode 1, 3)
21
Siemens Industry, Inc.
Application Note, App 6750
140-1328
2015-07-07
Venturi Air Valve Table Statement
V TABLE PT
Description
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
number 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
Supply
61 – 76
This portion of the table can be viewed and edited. The user enters a
point (any value 61 through 76)
into V TABLE PT and the corresponding
cfm and voltage values display in
TABLE FLOW and TABLE VOLTS
where they can be edited.
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.
Supply
Swap
120
Setting V TABLE PT to 120 instructs the controller to evaluate the values
in the inactive supply portion of the table using standard calibration
pass/fail logic. If they pass, they are exchanged with those in the active
supply portion of the table.
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.
NOTE:
The factory default value of SUP VLV STAT and GEX VLV STAT is NOTCAL. The
value of SUP VLV STAT or GEX VLV STAT is set whenever a calibration or table
transfer is performed as the last step of the calibration/table transfer. SUP VLV STAT
and GEX VLV STAT are never used for active control decisions.