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Steam humidifier valve controller · BACnet points list
Neptronic SKDESC-xB BACnet points list
Updated 28 October 2026
The SKDESC-xB is the electronic controller used on Neptronic steam injection humidifier valves. It communicates over BACnet MS/TP only and exposes setpoints, room and duct RH, PI tuning, high limit, network fallback settings, inputs and relay states.
This page lists 87 BACnet objects for the Neptronic SKDESC-xB — 30 of them writable — with each object’s type, instance number, name, engineering units and access. It is re-typed from Neptronic’s own free documentation, linked below.
- Manufacturer
- Neptronic
- Model
- SKDESC-xB
- Equipment
- Steam humidifier valve controller
- Equipment type
- Humidifiers
- BACnet objects
- 87 (30 writable)
- Transport
- BACnet MS/TP
- Firmware
- Not stated
- Default device instance
- 153000 + MAC address (153000 by default, MAC 0)
- Also known as
- SKDESC, SKDESCxB, ESCJx, ESCMx, Electronic Steam Controller
BMS integration notes: Neptronic SKDESC-xB
Set MSV 2 Control Mode to Network to drive the valve from the BMS, or feed room RH to AV 2 (after turning on BV 14 NetworkRoomRH) with the internal setpoint AV 1. Configure the network fallback timeout and fallback setpoint, and switch the system with BV 1.
Minimum points to map
The short list most integrators start with — enough to run the unit from a BMS. Map more as the job needs.
| Object | Name | Why | Access |
|---|---|---|---|
| BV 1 | PowerStatus | System power on/off | Write |
| MV 2 | ControlMode | Control mode: External, Internal or Network | Write |
| AV 1 | InternalStpnt | Internal RH setpoint | Write |
| AV 2 | RoomRH | Room RH (writable when BV 14 = On) | Write |
| AV 4 | SystemDemand | Humidity demand the controller is acting on | Read |
| BV 20 | AlarmRelayState | Alarm relay output; on when the controller signals an alarm | Read |
Enable & remote start
BV 1 PowerStatus (0 = Off, 1 = On) is writable; MSV 2 ControlMode selects External, Internal or Network control.
Heartbeat & communication loss
Network fallback is configured with AV 30 FallbackTimeout (0-900 s), AV 31 FallbackStpnt (0-100 %) and the AV 32 FallbackDownCntr countdown; the guide lists these objects but does not spell out the fallback sequence, so test it on site.
Sensors & values from the BMS
Room RH is written to AV 2 only while BV 14 NetworkRoomRH = On; duct RH is written to AV 3 only while MSV 3 HiLimitSensorSrc = Network. BV 15 enables an external RH setpoint.
Network setup
- MS/TP MAC defaults to 000 (000-254; 128-254 are non-token-passing slaves), baud auto-detects (Auto, 9600, 19200, 38400, 76800), Max_Master 127.
- Device instance defaults to 153000 + MAC and can be changed from the menu (password 637) or via Device Object_Identifier.
- Reinitialize Device over BACnet uses the password 'nep'.
Watch out for
- Out_of_Service automatically returns to False after 15 minutes by default (adjustable 0-120 min via a proprietary device property).
- A Copy Config can be run over BACnet, but the BACnet schedule is not copied.
- The controller does not send BACnet event notifications; poll alarm objects.
Neptronic SKDESC-xB BACnet objects
Type: AI, AO, AV, BI, BO, BV, MI/MO/MV (multi-state) · Access: Read read-only, Write writable, Command writable with a priority array.
| Description | States | |||||
|---|---|---|---|---|---|---|
| AI | 1 | SeparatorTempSig (ESCJx, ESCMx) | Separator temperature sensor signal (TS1) value | mV | Read | |
| AI | 2 | Jacket1TempSig (ESCJx) | Temperature sensor signal (TS2) value of jacket 1 | mV | Read | |
| AI | 3 | Jacket2TempSig (ESCJx) | Temperature sensor signal (TS3) value of jacket 2 | mV | Read | |
| AI | 4 | Jacket3TempSig (ESCJx) | Temperature sensor signal (TS4) value of jacket 3 | mV | Read | |
| AI | 5 | Jacket4TempSig (ESCJx) | Temperature sensor signal (TS5) value of jacket 4 | mV | Read | |
| AI | 6 | PCRTempSig (PCR Option) | Temperature sensor signal of PCR | Read | ||
| AI | 7 | ExternalSig | External input signal (AI1) | mV | Read | |
| AI | 8 | RoomRHSig | Room's relative humidity sensor signal (AI2) | mV | Read | |
| AI | 9 | DuctRHSig | Duct's relative humidity sensor signal | mV | Read | |
| AI | 10 | PCRWaterLevelSig | Water level signal of PCR | Read | ||
| AVmin | 1 | InternalStpnt | Internal setpoint value | % | Write | |
| AVmin | 2 | RoomRH | Relative humidity reading value of the room | % | Write | |
| AV | 3 | DuctRH | Relative humidity reading value of the duct | % | Write | |
| AVmin | 4 | SystemDemand | System demand value | Read | ||
| AV | 5 | SystemOutput | System output value | Read | ||
| AV | 6 | SeparatorTemp (ESCJx, ESCMx) | Separator temperature reading | °F or °C | Read | |
| AV | 7 | Jacket1Temp (ESCJx) | Temperature reading of jacket 1 | °F or °C | Read | |
| AV | 8 | Jacket2Temp (ESCJx) | Temperature reading of jacket 2 | °F or °C | Read | |
| AV | 9 | Jacket3Temp (ESCJx) | Temperature reading of jacket 3 | °F or °C | Read | |
| AV | 10 | Jacket4Temp (ESCJx) | Temperature reading of jacket 4 | Read | ||
| AV | 11 | PCRTemp (PCR Option) | Temperature reading of PCR | Read | ||
| AV | 12 | WorkingCapacity | Percentage value in full capacity | % | Write | |
| AV | 13 | SeparatorTempOffset (ESCJx, ESCMx) | Temperature sensor offset value of separator | °F or °C | Write | |
| AV | 14 | Jacket1TempOffset (ESCJx) | Temperature sensor offset value of jacket 1 | °F or °C | Write | |
| AV | 15 | Jacket2TempOffset (ESCJx) | Temperature sensor offset value of jacket 2 | °F or °C | Write | |
| AV | 16 | Jacket3TempOffset (ESCJx) | Temperature sensor offset value of jacket 3 | °F or °C | Write | |
| AV | 17 | Jacket4TempOffset (ESCJx) | Temperature sensor offset value of jacket 4 | °F or °C | Write | |
| AV | 18 | PCRTempOffset (PCR Option) | Temperature sensor offset value of PCR | Read | ||
| AV | 19 | RoomRHOffset | Relative humidity sensor offset value of the room | %RH | Write | |
| AV | 20 | CntrlDeadBand | Control deadband value | %RH | Write | |
| AV | 21 | CntrlPropRamp | Control proportional ramp value | %RH | Write | |
| AV | 22 | CntrlIntgrlTime | Control integral ramp value | %RH | Write | |
| AV | 23 | HiLimitStpnt | High limit setpoint value | %RH | Write | |
| AV | 24 | HiLimitPropRamp | High limit proportional ramp value | %RH | Write | |
| AV | 25 | DuctRHOffset | Relative humidity offset value of the duct | Read | ||
| AV | 26 | HiLimitMaxDemand | High limit maximum demand value | % | Read | |
| AV | 27 | EndOfSeasonDelay | End of season delay | h | Write | |
| AV | 28 | ServiceDelay | Delay in hours before a Service has to be performed | h | Write | |
| AV | 29 | ServiceRunTime | Service runtime counter | h | Read | |
| AV | 30 | FallbackTimeout | Network fallback timeout | s | Write | |
| AV | 31 | FallbackStpnt | Network fallback setpoint | % | Write | |
| AV | 32 | FallbackDownCntr | Network fallback downcounter | s | Write | |
| AV | 33 | TotalRunTime | Total system runtime | h | Read | |
| AV | 34 | CntrlOutputSig | Control valve output signal | mV | Read | |
| AV | 35 | MicroCntrlTemp | Microcontroller temperature reading | °F or °C | Read | |
| AV | 36 | BoardTemp | Temperature reading of the PC board | °F or °C | Read | |
| AV | 37 | CntrlDerivativeTime | Control derivative time | Read | ||
| AV | 38 | DuctStpntMin | Minimum setpoint value of duct | Read | ||
| AV | 39 | DuctStpntMax | Maximum setpoint value of duct | Read | ||
| AV | 41 | DuctPropRamp | Proportional ramp value of duct | Read | ||
| AV | 42 | DuctIntgrlTime | Integral time value of duct | Read | ||
| AV | 43 | DuctDerivativeTime | Derivative time value of duct | Read | ||
| AV | 44 | ControlDemand | Control demand value | Read | ||
| AV | 45 | DynamicDuctStpnt | Dynamic duct setpoint value | Read | ||
| AV | 46 | DuctDemand | Duct demand value | Read | ||
| AV | 47 | PCRSupplySig (PCR Option) | Supply signal value of PCR | Read | ||
| AV | 48 | PCRSupply (PCR Option) | Supply value of PCR | Read | ||
| BI | 1 | ExternalDemandInputState | Digital external demand input state | Read | 0=OFF, 1=ON | |
| BI | 2 | AirflowInputState | Airflow input state | Read | 0=OFF, 1=ON | |
| BI | 3 | HiLimitInputState | High limit input state | Read | 0=OFF, 1=ON | |
| BI | 4 | InterlockInputState | Interlock input state | Read | 0=OFF, 1=ON | |
| BVmin | 1 | PowerStatus | System's power status | Write | 0=OFF, 1=ON | |
| BV | 2 | ServiceWarning | Service warning | Read | 0=OFF, 1=ON | |
| BV | 3 | ServiceAlarm | Service alarm | Read | 0=OFF, 1=ON | |
| BV | 4 | AirFlowCutout | Air flow cutout state | Read | 0=OFF, 1=ON | |
| BV | 5 | HiLimitCutout | High limit cutout state | Read | 0=OFF, 1=ON | |
| BV | 6 | InterlockCutout | Interlock cutout state | Read | 0=OFF, 1=ON | |
| BV | 7 | TempSensorDefect | Temperature sensor defect | Read | 0=OFF, 1=ON | |
| BV | 8 | RoomRHSensorDefect | Room relative humidity sensor defect | Read | 0=OFF, 1=ON | |
| BV | 9 | DuctRHSensorDefect | Duct relative humidity sensor defect | Read | 0=OFF, 1=ON | |
| BV | 10 | FloodedSteamTrap | Flooded steam trap | Read | 0=OFF, 1=ON | |
| BV | 11 | DisplayUnits | Display units | Write | 0=Metric, 1=Imperial | |
| BV | 12 | EconoMode | Economic mode | Write | 0=OFF, 1=ON | |
| BV | 13 | ExternalSigRange | External input signal range | Write | 0=2 to 10V, 1=0 to 10V | |
| BV | 14 | NetworkRoomRH | Network room relative humidity | Write | 0=OFF, 1=ON | |
| BV | 15 | ExternalRHStpnt | External relative humidity setpoint | Write | 0=OFF, 1=ON | |
| BV | 16 | ExternalRHStpnt | Read | |||
| BV | 17 | HiLimitRHSigRange | High limit relative humidity signal range | Write | 0=OFF, 1=ON | |
| BV | 18 | RunsWhenServiceAlarm | Runs when service alarm is active | Write | 0=OFF, 1=ON | |
| BV | 19 | IsoValveOutState | Isolating valve output state | Read | 0=OFF, 1=ON | |
| BVmin | 20 | AlarmRelayState | Alarm relay output state | Read | 0=OFF, 1=ON | |
| BV | 21 | SteamRelayState | Steam relay output state | Read | 0=OFF, 1=ON | |
| BV | 22 | PCRReliefValveOutState (PCR Option) | Relief valve output state of PCR option | Read | ||
| MV | 1 | Language | Sytem language | Write | 1=ENG | |
| MVmin | 2 | ControlMode | Control mode | Write | 1=External, 2=Internal, 3=Network | |
| MV | 3 | DuctSensorSrc | Duct sensor source | Read | ||
| MV | 4 | PCRWaterLevel (PCR Option) | PCR water level | Read | 1=Above High, 2=Above Low, 3=Below Low, 4=Error |
No points match these filters.
Integration notes
- Points marked 'object available as per system configuration' depend on the unit options.
- Empty 'W?' entries in the guide are treated as read-only.
Check it against the live device. A points list tells you what the controller can expose; the unit in front of you may differ by firmware or installed options. Easy BACnet scans a network for BACnet IP devices from an Android phone, reads every object on the SKDESC-xB and exports what it actually has to Excel — free. New to BACnet? Start with what a BACnet points list is and what the object types mean.
Questions about the Neptronic SKDESC-xB
How many BACnet points does the Neptronic SKDESC-xB have?
This list has 87 BACnet objects: 10 analog inputs, 47 analog values, 4 binary inputs, 22 binary values, 4 multi-state values. The exact set on a given unit depends on its firmware, installed options and configuration.
Which Neptronic SKDESC-xB BACnet points are writable?
30 of the 87 objects accept a write. Points marked Command have a priority array: a write holds until it is released, so release it back to automatic when you are done.
Where is the official Neptronic SKDESC-xB BACnet documentation?
The source is SKDESC-xB Series Electronic Steam Controller BACnet Communication Module User Guide (SKDESCXB-BACnet-250905-EUA), revision 2025-09-05, published free by Neptronic at https://www.neptronic.com/Humidifiers/PDF/2025/SKDESCXB-BACnet-250905-EUA.pdf.
What are the minimum BACnet points to integrate the Neptronic SKDESC-xB?
Start with BV 1 PowerStatus (System power on/off); MV 2 ControlMode (Control mode: External, Internal or Network); AV 1 InternalStpnt (Internal RH setpoint); AV 2 RoomRH (Room RH (writable when BV 14 = On)); AV 4 SystemDemand (Humidity demand the controller is acting on); BV 20 AlarmRelayState (Alarm relay output; on when the controller signals an alarm).
How do I enable BMS control of the Neptronic SKDESC-xB?
BV 1 PowerStatus (0 = Off, 1 = On) is writable; MSV 2 ControlMode selects External, Internal or Network control.
Does the Neptronic SKDESC-xB need a BACnet heartbeat or have a communication timeout?
Network fallback is configured with AV 30 FallbackTimeout (0-900 s), AV 31 FallbackStpnt (0-100 %) and the AV 32 FallbackDownCntr countdown; the guide lists these objects but does not spell out the fallback sequence, so test it on site.
Can the BMS supply sensor values to the Neptronic SKDESC-xB?
Room RH is written to AV 2 only while BV 14 NetworkRoomRH = On; duct RH is written to AV 3 only while MSV 3 HiLimitSensorSrc = Network. BV 15 enables an external RH setpoint.
How do I check these points on the real SKDESC-xB?
Scan the network with a BACnet IP browser such as Easy BACnet, open the device and compare its object list with this table. Anything missing is usually an option that isn't installed or a point that is disabled in the controller's configuration.
More Neptronic BACnet points lists
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Neptronic EVCB14NxT4X VAV Controller (external motor)
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Neptronic EVCB44N Series VAV Controller
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Neptronic EVCBM Dual Duct VAV Controller
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Neptronic SKG4
Neptronic SKG4 gas-fired steam humidifiers with up to four humidifier modules.
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Neptronic SKH4
Neptronic SKH4 high-pressure water atomizing humidifiers and evaporative coolers with up to six zones (A-F).
Also known as: SKH4 high-pressure atomizer, SKH4 BACnet - Reverse osmosis water treatment unit
Neptronic SKRO
Neptronic SKRO reverse osmosis water treatment units feeding humidifiers.
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Neptronic SKS4
Neptronic SKS4 steam-to-steam (boiler steam heated) humidifiers.
Also known as: SKS4 steam to steam humidifier, SKS4 BACnet - Evaporative humidifier
Neptronic SKV
Neptronic SKV evaporative (media) humidifiers with up to four modules.
Also known as: SKV evaporative humidifier, SKV BACnet - Evaporative cooler / humidifier
Neptronic SKVF
Neptronic SKVF series evaporative coolers (also used for humidification).
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Neptronic TFxB Series Thermostat Controller
Neptronic TFxB24 communicating thermostats for 2-pipe and 4-pipe fan coils and zone heating/cooling, including the humidity (TFHB) and OE variants.
Also known as: TFCB24F3XYZ1, TFCB24F3XY2, TFHB24F3XYZ1, TFHB24F3XYZ2, TFCB24P3-OE1, TFHB24P3-OE1, TFHB24P3-OE2, TFxB24
Source: SKDESC-xB Series Electronic Steam Controller BACnet Communication Module User Guide · SKDESCXB-BACnet-250905-EUA · rev. 2025-09-05. Object names, instances and units are reproduced as published; descriptions are our own.