User Guide
BACnet Int egration Guide – DOAS_08.000 Rev 2 Page | 5
BM S Watchdog Enabled Control
BM SWATCHDOG
When directly commanding fans speeds, damper positions, or sending sensor values, the unit cont roller requires the
BM S Watchdog point to be writt en to on a recurring basis. This tells the unit controller that the BM S is still actively
communicating.
Object Variable Description Active Text Inactive Text
BM S W atchdog
The BM S Watchdog must be writ ten to True (1) regularly to verify communication is est ablished between the unit controller and t he BM S headend
system. If the BMS Wat chdog value remains False(0) for longer than the Timeout Delay (15 minut es, adjustable), an alarm is generat ed and t he
contr oller falls back t o local cont rol and sensor values, as applicable, inst ead of using BMS com manded values.
BV-1 BM S_Wat chdog BM S Watchdog command Active Inactive
BV-24 BM S_Watchdog_Active Status of the BM S wat chdog ping. Active Inactive
CONTROLLING AIRFLOW DEVICES
If desired, the speeds and posit ions of airflow devices can be controlled directly using BACnet commandable point s. To
cont rol the devices via the BM S, the BM S Watchdog requirement s must be satisfied.
Object Variable Description Active Text Inactive Text
Fan Controls
Fan speeds can be cont rolled directly t hough BM S point s. The binary point s enable the BM S t o take control and the analog values command the
speeds as a percentage betw een t he allowed minim um and maximum values set in the cont roller.
Supply Fan
BV-17 SF_Cont rol_Source_BM S Allow s the BM S to control supply fan speed BM S Local
AV-36 SF_Control_Signal_BM S Supply Fan Command Speed
Real (%)
* M in=50%; M ax=100%
Exhaust Fan
BV-18 EF_Control_Source_BM S Allows t he BM S t o cont rol exhaust fan speed BM S Local
AV-37 EF_Cont rol_Signal_BM S Exhaust Fan Command Speed
Real (%)
M in=25%; M ax=100%
Outdoor Air/ Recirculation Air Damper Control
The out door air damper posit ion can be cont rolled directly by the BM S to adjust the mixt ure of out door air and recirculation air on unit s configured for
recirculat ion. M inimum and maximum values for occupied and unoccupied mode set at the unit cont roller are enforced.
BV-19 OAD_Contr ol_Source_BM S Allow s the BM S to control OAD position
BM S Local
AV-38 OAD_Contr ol_Signal_BM S Out side Air Damper Cont r ol Signal via BM S
Real (%)
M in=0%; M ax=100%
* Typical range for st andard configuration unit, please verify at point min and max propert ies.
SENDING SENSOR VALUES
Sensor values required for sequence operation can be sent to the cont roller over dedicated BM S point s in place of a
sensor wired to the controller (local sensor). When values are communicated to the cont roller over BM S, the BM S
Watchdog must be satisfied. If the watchdog isn’t satisfied, the cont roller reverts to the local sensor (if installed and
valid) to control the unit or falls back to local control unt il the BM S watchdog is satisfied.
Object Variable Description Active Text Inactive Text
BM S W riteable Sensor Values
To write the sensor values over BM S, first command the controller t o use the BM S value using the corresponding binary value and then use the
corresponding analog value t o send the sensor value.
Sensor Sources
BV-7 Outside_RH_Source_BM S Out side RH Source Select ion BM S Local
BV-8 Outside_Temp_Source_BM S Out side Temp Source Select ion BM S Local
BV-9 Return_RH_Source_BM S Return RH Source Select ion BM S Local
BV-10 Return_Temp_Source_BM S Ret urn Temp Source Selection BM S Local
BV-11 Space_1_CO2_Source_BM S Space 1 CO2 Source Select ion BM S Local
BV-12 Space_2_CO2_Source_BM S Space 2 CO2 Source Select ion BM S Local
BV-13 Return_CO2_Sour ce_BM S Return CO2 Source Selection BM S Local
BV-14 Space_RH_Source_BM S Space RH Source Selection BM S Local
BV-15 Space_Stat ic_Source_BM S Space Stat ic Source Selection BM S Local
BV-16 Space_Temp_Source_BMS Space Temp Source Selection BM S Local