Device Parameters (ACS931 / ACS941 / AST20) - Basic Documentation - GDB181.1E/BA - GDB181.1EMBA - GLB181.1E/BA

VAV Compact Controller BACnet MS/TP G..B181.1E/BA

Product Family
Product Group
Damper actuators
Content Language
Content Type
Technical Documentation > Basic Documentation
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Parameter Range Description Factory setting
Setpoint 0..100%

Setpoint to VAV controller.
0% 🡪 Vmin

100% 🡪 Vmax

Actual position 0..100% Damper position, depends on setting for position adaptation N/A
Actual Flow abs. 0..65’535 m3/h Actual volume flow in m3/h or l/s N/A
Actual Flow % 0..100% Actual volume flow relative to Vnom in % N/A
Actual pressure 0..300 Pa Actual differential pressure N/A
Override control Open / Close / Sop / Min / Max
Operating mode VAV / POS

VAV = Setpoint 0..100% volume flow

POS = Setpoint 0..100% damper position

Opening direction CW / CCW Opening direction of air damper CW
Positioning Absolute / Adaptive

Adaption of actual opening range to position feedback 1)

Off = No adaptation / mapping
0°..90° 🡪 0..100 %

On = Pos. adaptation / mapping e.g.
0°..60° 🡪 0..100 %

Vmin -20..100% Minimum air volume flow 0 %
Vmax 20..120% Maximum air volume flow 100 %
Vnom 0..65‘535 m3/h Nominal air volume flow 2) 100 m3/h
Vn (Coefficient) 1..3.16 Characteristic value for the VAV box; set by the OEM 1.00
dpnom 30..300 Pa Nominal differential pressure, corresponds to Vn 300 Pa
Altitude asl. 0..5000m
in 500m steps
Altitude level correction, select n*500m value closest to altitude of installation 500 meters
Unit vol. flow m3/h / l/s / cfm Unit in which the volume flow is displayed m3/h
Unit Vmin & Vmax %, m3/h or l/s Unit in which Vmin / Vmax are entered %
Address 1..245 RS-485 bus address
Baudrate Auto, 9600, 19200..115200 RS-485 baudrate Auto
Transmission Format 1-8-E-1, 1-8-E-2, 1-8-N-1 Start- / Stop-Bit, Parity 1-8-N-1
Termination Off / On RS-485 bus termination, electronically switchable Off
Max. Master 1..255 BACnet MS/TP network parameter, should be set close to the highest network address in a segment. 255
Device Object ID 0..10’000 BACnet Device Object ID 10’000

1) Adaptive positioning must not be activated whil the actuator is mechanically jammed

2) Value used for displaying / not used for volume flow control loop