Vsmart Technical Manual
Block diagram
Motor 1
Motor 2
Heater 1
Heater 2
Temperature sensor
The block diagram shows the system for a VS22. The VS02
would not have the heater but would have all the other
Power supply
The first part of the system is the power supply. It
supplies 24VDC power to the Vsmart and the vent motors.
Typically, the motors draw several Amps, so size the power
supply to handle 2 motors at one time. Bartlett
Instrument’s VSPS 120-24 is designed to take line power and
provide 24VDC power to the Vsmart to run 2 typical motors
with a 5 Amp maximum output for each motor.
The connection between the power supply and Vsmart should
be as short as possible with as large of wire as feasible
to prevent too much Voltage drop. 12 gauge wire is usually
adequate for runs under 25’. This connection carries the
current for both motors.
The connection between the Vsmart and the motors only carry
the load of one motor but will be longer than the
connection between the power supply and controller. Check
with the motor manufacturer for allowable Voltage drop and
use an on line Voltage drop calculator to determine the
required wire size.
The thermistor can be extended up to 300’ without causing
calibration errors. Use wire that is UV tolerant or is
shielded from sun light.
The connections to the heater can be standard thermostat
The brain of the system is the Vsmart. The Vsmart uses a
thermistor placed in the crop to sense the temperature and
then activates either heating or cooling (24VDC motors) to
drive the temperature to the programmed set point. The
rest of the document will describe the controller
The motors driven by the Vsmart are 24VDC reversible gear
motors for roof vents or roll up sides.
The Vsmart has dry contact to connect to a heater’s low
Voltage thermostat input. A relay can be added to allow
each heat output to control multiple heaters.
24VDC, Fused at 5A per motor
Polarity of output switches to
change from open to close.
If motor runs backwards, reverse
Leads at the output connection
Heating outputs
Model VS22 has 2 heating outputs.
The outputs are dry contacts
Maximum Voltage is 48VDC
Maximum current is 1 A.
Cooling Control Algorithm
The Vsmart’s cooling control algorithm is very unique.
The “smart” alorithm’s goal is to keep the temperature
close to the set point without over working the motors.
The Vsmart will vary it’s response based on varying outdoor
conditions. The Vsmart tracks the temperature’s variation
and rate of change to ascertain the outside conditions and
to determine how aggressively to control the motor
movement. Rapid climbs in temperature indicate a sunny day
so the cooling can be more aggressive. Quick descents in
temperature mean its cold outside and the cooling should be
more cautious. Transitioning from night to day is also a
time for restrained cooling. The transition can be
detected by a long period of the temperature below the set
point and then a steady climb to the set point and above.
The controller switches to more aggressive cooling once the
temperature has been above the set point for the programmed
period indicating that the sun has risen higher.
Bright cool spring days often cause a controller to
over react and cause roll up walls to go up and down. (“YOYO” is the technical term) The Vsmart detects YO-YO
conditions and limits the controller response to prevent
future over reaction.
Operating times
All movements of the motors are in multiples of the
“on time” unless the conditions indicate that full open or
full close are required. “on time” is set as one of the
menu options. The default setting for “on time” is 10
seconds (range is from 1-15s). Longer on times are used
for slower moving vents. The variations in the temperature
and the amount of motor movement are tracked to calculate
the number of “on times” needed to drive the temperature
toward the set point. The number of “on times” in the open
or close direction is calculated every minute.
At the night to day transition, there is a burst
option to help a roll up wall get above a knee wall when
the temperature first exceeds the set point. Burst adds an
additional 3 “on times” to the first open time of the day.
For instance, if “on time” is 10 seconds, at the night to
day transition the burst will be 30 seconds.
Option Menu Description
There are 4 selections in the options menu – STYLE of
controller, BURST mode at the beginning of the day,
SEPARATION between motor 1 and motor 2, and the PERIOD.
STYLE – The Vsmart can be set to
is only for cooling and the VS22
Style should be set to match the
ensure hardware is compatible to
a VS02 or VS22. The VS02
includes 2 heat outputs.
model on the faceplate to
the software selection.
BURST – The first time the vent opens after the vent has
been completely closed, and the burst mode is enabled, the
Vsmart will add a 3-“on time” burst to the opening amount.
The burst mode is used with a roll up wall that has a roll
lock or knee wall that requires significant motor movement
before the wall starts to open.
The burst mode can be set to off (neither motor
bursts), 1 on (only motor 1 bursts), 2 on (only motor 2
bursts), or both (both motors burst).
SEPARATION – Motor 1 can be the primary cooling output and
motor 2 can respond several degrees above the set point
( separation on ) or both cooling outputs control to the
same set point (separation off). Roll up walls on opposing
sides of a house work best with separation off. Houses
with a roof vent and end vent work best with separation on.
PERIOD – This is the number of minutes certain conditions
must exist before the controller adjusts its control
status. The default value is 40 minutes. Reduce the
period if you have a large house that responds slowly or if
you use a short “on time”.
Condition 1 - The controller will trigger another burst
when the cooling outputs have been at full close for longer
than “period”. A long period without cooling indicates to
the Vsmart either a night to day or cloudy to sunny
Condition 2 – The Vsmart will end the anti YO-YO settings
and will be more aggressive cooling after the temperature
has been above the cooling set point for a time greater
than “period”. This timer is reset when the temperature
dips below the cooling set point. Reduce the period if the
temperature exceeds the set point and the response is too
Condition 3 – For the VS22, the cool to heat is increased
if the temperature is above the cooling set point for a
time greater than the “period” and the heat to cool delay
is increase if the temperature is below the heating set
point longer than “period”.
The option menu is entered by holding a key during power
up. The options are style, burst, separation of vent 1 and
vent 2 set points and maximum period.
To get into the edit menu, press and hold a key while power
is applied to the controller. Release the key after a long
beep. The display will show “styl”.
At “styl” press enter to move to burst or press an arrow to
change the model between VS02 or VS22. Press enter to
store the style of controller.
The display will show “brst”. Press enter to skip changing
the burst setting or press an arrow to change the burst
mode. Press the arrow to change between off, 1 on, 2 on or
both and then press enter.
The display will show “Sep” for separation between set
points for the two vents. Press enter to skip to period or
press an arrow to adjust separation on or off. Press enter
to accept the “SEP” setting.
The display will now show “PER” for period. Press enter to
skip changing period or press an arrow key to change the
period. Valid setting for period range from 0 to 40. If
the temperature has been above the set point for less time
than the period the open time is divided by 2 for less
aggressive control. Press enter to store the period.
The display will show “cplt”.
Press a key to start
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