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ElectroVap ERS / RTH resistive steam humidifier (V3 controller)

Resistive steam humidifier · BACnet points list

Devatec ElectroVap ERS / RTH resistive steam humidifier (V3 controller) BACnet points list

Updated 12 November 2026

Short answer

The ElectroVap ERS and RTH ranges are resistive-element steam humidifiers built around the same V3 main board (an Armstrong motherboard), which speaks Modbus RTU or BACnet MS/TP on RS485. The BACnet map exposes valve, contactor, relay and A1-A10 alarm states as Binary Inputs, a start/stop Binary Output, run data and counters as Analog Inputs, and setpoints, control signal type and PID settings as Analog Values.

This page lists 66 BACnet objects for the Devatec ElectroVap ERS / RTH resistive steam humidifier (V3 controller) — 15 of them writable — with each object’s type, instance number, name, engineering units and access. It is re-typed from Devatec’s own free documentation, linked below.

Manufacturer: Devatec
Model: ElectroVap ERS / RTH resistive steam humidifier (V3 controller)
Equipment: Resistive steam humidifier
Equipment type: Humidifiers
BACnet objects: 66 (15 writable)
Transport: BACnet MS/TP
Firmware: Application software 1, firmware 1 (PICS)
Default device instance: 0x02000000 + vendor ID x 1000 + MS/TP address (settable in the menu)
Also known as: ERS, ERS-HC, ERS-LC, RTH-HC, RTH-LC, ElectroVap ERS, ElectroVap RTH, Devatec ERS, Devatec RTH, Armstrong Motherboard
Source document: ElectroVap ERS Series Instruction & Operation Manual · DT_ERS-V3_EN REV B.3

Download CSV 66 rows Download EDE B.I.G.-EU JSON Manufacturer PDF ↗ Compare with your scan Download Easy BACnet Mobile App Google Play

Reference only, provided as-is: verify against Devatec’s current documentation and the live device before use. Not official Devatec information. Terms of use.

BMS integration notes: Devatec ElectroVap ERS / RTH resistive steam humidifier (V3 controller)

Integration in brief

Wire RS485 to J2, choose BACnet MS/TP and an address in the controller menu, then start/stop the humidifier with BO 0 and send demand or RH through AV 3 (or use the unit's own setpoint AV 4). Watch run status, steam output and the alarm relay.

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
BO 0	On/Off BMS command	Start/stop (1 = start requested)	Write
AV 3	Digital Rh value or digital demand	Demand or RH from the BMS, 1-100 %	Write
AV 4	Rh set point	Humidity setpoint, %RH	Write
AI 4	Run status	Run status code	Read
AI 3	Steam output	Steam output, 10 x kg/h	Read
AI 2	Demand	Current demand, %	Read
BI 6	Alarm relay	Alarm relay on	Read
BI 19	Rh sensor error	Humidity sensor fault	Read

Enable & remote start

BO 0 On/Off BMS command starts (1) or stops (0) the unit.

Sensors & values from the BMS

AV 3 takes a digital RH value or digital demand (1-100 %) from the BMS; AV 9 sets whether the control signal is a digital command, a digital sensor or an analog input.

Network setup

RS485 on connector J2 (1 Data-, 2 Data+, 3 GND); SW1 switches the line termination and bias resistors.
Baud 2400 to 230400 (9600 default), 8 data bits, no parity; BACnet MS/TP uses 1 stop bit.
Device instance defaults to 0x02000000 + vendor ID x 1000 + station address and can be set in the menu.

Watch out for

The adjustment and PID AVs are tuning values; leave them at factory settings unless told otherwise.
Totals are split into two 16-bit words (MSB/LSB); combine them in the BMS.
Tank 2 points only apply to two-tank units (AI 26).

Devatec ElectroVap ERS / RTH resistive steam humidifier (V3 controller) 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.

Note: the source document has no read/write column, so access here is inferred from the object type (inputs read-only, values writable). Confirm on the live controller before writing.

66 of 66 shown

Type

Access

Units

Show

Devatec ElectroVap ERS / RTH resistive steam humidifier (V3 controller) BACnet Points List
			Description			States
BI	0	inlet valve	Fill valve		Read	0=No filling, 1=Filling
BI	1	drain valve	Drain valve		Read	0=No drain, 1=Drain
BI	2	contactor K1	Heater contactor K1		Read	0=Off, 1=On
BI	3	contactor K3	Heater contactor K3		Read	0=Off, 1=On
BI	4	Blower pack	Blower pack output		Read	0=Off, 1=On
BI	5	Service relay	Service relay		Read	0=Off, 1=On
BImin	6	Alarm relay	Alarm relay		Read	0=Off, 1=On
BI	7	On/off Relay	On/off relay		Read	0=Off, 1=On
BI	8	High limite sw	High limit switch		Read	0=Not detected, 1=Detected
BI	9	Alarm A1 state	Alarm A1 active		Read	0=Off, 1=On
BI	10	Alarm A2 state	Alarm A2 active		Read	0=Off, 1=On
BI	11	Alarm A3 state	Alarm A3 active		Read	0=Off, 1=On
BI	12	Alarm A4 state	Alarm A4 active		Read	0=Off, 1=On
BI	13	Alarm A5 state	Alarm A5 active		Read	0=Off, 1=On
BI	14	Alarm A6 state	Alarm A6 active		Read	0=Off, 1=On
BI	15	Alarm A7 state	Alarm A7 active		Read	0=Off, 1=On
BI	16	Alarm A8 state	Alarm A8 active		Read	0=Off, 1=On
BI	17	Alarm A9 state	Alarm A9 active		Read	0=Off, 1=On
BI	18	Alarm A10 state	Alarm A10 active		Read	0=Off, 1=On
BImin	19	Rh sensor error	Humidity sensor fault		Read	0=Off, 1=On
BOmin	0	On/Off BMS command	Start/stop from the BMS		Write	0=Off (device off), 1=On (start required)
BV	1	EOS drain statue	End-of-season drain		Write	0=Off, 1=On
AI	0	Type unit	Unit type code		Read	4=ERS, 5=RTH-LC, 6=ERS-HC, 7=ERS LC
AI	1	Reg version	Register map version		Read
AImin	2	Demand	Current demand	%	Read
AImin	3	Steam output	Steam output, value = 10 x kg/h	kg/h	Read
AImin	4	Run status	Operating status		Read	1=Idle, 2=Preheat cycle, 3=Steam production, 4=Manual drain, 5=Ready for use, 6=Maintenance due, 7=Fault, 8=Aquastat on
AI	5	Estimated time to service	Hours to next service	h	Read
AI	6	Production since last service (MSB)	Steam since last service, high word	kg	Read
AI	7	Production since last service (LSB)	Steam since last service, low word	kg	Read
AI	8	Total production (MSB)	Total steam, high word	kg	Read
AI	9	Total production (LSB)	Total steam, low word	kg	Read
AI	10	Total run time (MSB)	Total run time, high word	h	Read
AI	11	Total run time (LSB)	Total run time, low word	h	Read
AI	12	Remaining idle time to EOS drain	Idle hours left before end-of-season drain	h	Read
AI	13	Control signal value	Control signal, 10 x V or 10 x mA or %		Read
AI	14	Temperature tank 1	Tank 1 water temperature	°C	Read
AI	15	Temperature tank 2	Tank 2 water temperature	°C	Read
AI	16	Alarm A2 counter	A2 alarm count		Read
AI	17	Alarm A3 counter	A3 alarm count		Read
AI	18	Alarm A6 counter	A6 alarm count		Read
AI	19	Alarm A7 counter	A7 alarm count		Read
AI	20	Alarm A8 counter	A8 alarm count		Read
AI	21	Partial drain timer	Partial drain timer, 10 x s	s	Read
AI	22	PWM main supply	PWM trigger value		Read
AI	23	PWM counter	PWM counter		Read
AI	25	Max production capability	Maximum steam capacity		Read
AI	26	Number of tank	Number of tanks, 1 or 2		Read
AI	27	Unit type ID	Unit type code		Read
AI	28	Unit voltage type	Unit voltage code		Read
AI	29	Water level status	Water level detected, 0-3		Read
AI	30	Power consumed	Power consumed	kW	Read
AI	31	Max power rating	Maximum power rating	kW	Read
AVmin	3	Digital Rh value or digital demand	RH or demand from the BMS, 1-100 %	%	Write
AVmin	4	Rh set point	Humidity setpoint, 1-100 %	%RH	Write
AV	5	EOS drain timer	End-of-season drain delay, 1-120 h	h	Write
AV	6	Service counter	Service interval, kg/100, 1-65000		Write
AV	7	Aquastat status	Tank keep-warm aquastat		Write	1=Activate, 2=Deactivate
AV	8	Aquastat setpoint	Aquastat setpoint, 10-80 °C	°C	Write
AV	9	Control signal type	Control signal type		Write	20=OnOff, 21=digital ctrl, 22=control digital, 23=0-10V ctrl, 24=1-5V ctrl, 25=4-20mA ctrl, 26=0-10V sensor, 27=0-5V sensor
AV	11	Control signal adjustment	Control signal trim, raw minus 128 = %, 123-133		Write
AV	13	Temperature 1 adjustment	Tank 1 temperature trim, raw minus 128, 123-135		Write
AV	14	Temperature 2 adjustment	Tank 2 temperature trim, raw minus 128, 123-136		Write
AV	15	Proportional factor of PID	PID P factor, 0-50, typ. 20		Write
AV	16	Integral factor PID	PID I factor, 0-50		Write
AV	17	Derivative factor PID	PID D factor, 0-50		Write

Object ID lookup: Devatec ElectroVap ERS / RTH resistive steam humidifier point IDs by name

BI0inlet valve
BI1drain valve
BI2contactor K1
BI3contactor K3
BI4Blower pack
BI5Service relay
BI6Alarm relay
BI7On/off Relay
BI8High limite sw
BI9Alarm A1 state
BI10Alarm A2 state
BI11Alarm A3 state
BI12Alarm A4 state
BI13Alarm A5 state
BI14Alarm A6 state
BI15Alarm A7 state
BI16Alarm A8 state
BI17Alarm A9 state
BI18Alarm A10 state
BI19Rh sensor error
BO0On/Off BMS command
BV1EOS drain statue
AI0Type unit
AI1Reg version
AI2Demand
AI3Steam output
AI4Run status
AI5Estimated time to service
AI6Production since last service (MSB)
AI7Production since last service (LSB)
AI8Total production (MSB)
AI9Total production (LSB)
AI10Total run time (MSB)
AI11Total run time (LSB)
AI12Remaining idle time to EOS drain
AI13Control signal value
AI14Temperature tank 1
AI15Temperature tank 2
AI16Alarm A2 counter
AI17Alarm A3 counter
AI18Alarm A6 counter
AI19Alarm A7 counter
AI20Alarm A8 counter
AI21Partial drain timer
AI22PWM main supply
AI23PWM counter
AI25Max production capability
AI26Number of tank
AI27Unit type ID
AI28Unit voltage type
AI29Water level status
AI30Power consumed
AI31Max power rating
AV3Digital Rh value or digital demand
AV4Rh set point
AV5EOS drain timer
AV6Service counter
AV7Aquastat status
AV8Aquastat setpoint
AV9Control signal type
AV11Control signal adjustment
AV13Temperature 1 adjustment
AV14Temperature 2 adjustment
AV15Proportional factor of PID
AV16Integral factor PID
AV17Derivative factor PID

Integration notes

The manual's table has no read/write column; access is inferred from the Modbus register area (coils and holding registers writable).
The table gives each object's class, instance, hex ID and a description; the description is used as the object name.
AV 3 is printed with class "A0" and ID 00000003; its Modbus holding register (40004) and place in the AV block point to Analog Value 3. Check with a scan.
Several values are scaled: steam output and partial drain timer are 10x, totals are split into MSB/LSB words, and the adjustment AVs are raw minus 128 = %.
The ERS-LC, RTH-HC and RTH-LC manuals (rev B.2) print the same objects and IDs with older wording (Fill valve, Contactor 1, Contactor 2, Onoff Relay); this list follows the newer ERS rev B.3.
AI 24 is not printed.

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. This list is provided as-is for reference only and may contain mistakes — confirming it before you write, map or commission anything is up to you (terms). Easy BACnet scans a network for BACnet IP devices from an Android phone, reads every object on the ElectroVap ERS / RTH resistive steam humidifier (V3 controller) 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 Devatec ElectroVap ERS / RTH resistive steam humidifier (V3 controller)

How many BACnet points does the Devatec ElectroVap ERS / RTH resistive steam humidifier (V3 controller) have?

This list has 66 BACnet objects: 31 analog inputs, 13 analog values, 20 binary inputs, 1 binary output, 1 binary value. The exact set on a given unit depends on its firmware, installed options and configuration.

Which Devatec ElectroVap ERS / RTH resistive steam humidifier (V3 controller) BACnet points are writable?

15 of the 66 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. The source has no read/write column, so this is inferred from object type.

Where is the official Devatec ElectroVap ERS / RTH resistive steam humidifier (V3 controller) BACnet documentation?

The source is ElectroVap ERS Series Instruction & Operation Manual (DT_ERS-V3_EN REV B.3), published free by Devatec at https://www.devatec.com/wp-content/uploads/2024/12/DT_ERS-V3_EN_REV-B.3_L-2.pdf.

What are the minimum BACnet points to integrate the Devatec ElectroVap ERS / RTH resistive steam humidifier (V3 controller)?

Start with BO 0 On/Off BMS command (Start/stop (1 = start requested)); AV 3 Digital Rh value or digital demand (Demand or RH from the BMS, 1-100 %); AV 4 Rh set point (Humidity setpoint, %RH); AI 4 Run status (Run status code); AI 3 Steam output (Steam output, 10 x kg/h); AI 2 Demand (Current demand, %); BI 6 Alarm relay (Alarm relay on); BI 19 Rh sensor error (Humidity sensor fault).

How do I enable BMS control of the Devatec ElectroVap ERS / RTH resistive steam humidifier (V3 controller)?

BO 0 On/Off BMS command starts (1) or stops (0) the unit.

Can the BMS supply sensor values to the Devatec ElectroVap ERS / RTH resistive steam humidifier (V3 controller)?

AV 3 takes a digital RH value or digital demand (1-100 %) from the BMS; AV 9 sets whether the control signal is a digital command, a digital sensor or an analog input.

How do I check these points on the real ElectroVap ERS / RTH resistive steam humidifier (V3 controller)?

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 Devatec BACnet points lists

Electrode steam humidifier
Devatec ElectroVap MC (ELMC) electrode steam humidifier (V3 controller)
Devatec ElectroVap ELMC electrode steam humidifiers with the V3 controller; the same table is printed for the EHU-750, KIT MC and SB steam-bath generator.
32 objects · 10 writable · DT_ELMC-V3-EN REV B.1
Also known as: ELMC, ElectroVap MC, ElectroVap ELMC, EHU-750, EHU 750, KIT MC, CMC, Steam Bath SB, Devatec ELMC

Source: ElectroVap ERS Series Instruction & Operation Manual · DT_ERS-V3_EN REV B.3. Object names, instances and units are reproduced as published; descriptions are our own.