Communication profile MVA009

Radio communication is periodically and bidirectional exclusively following the Micropelt designed and MVA005 customized EnOcean Equipment Profile EEP A5 20-06 (Harvesting-powered actuator with local temperature offset control (BI-DIR).

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Protocol data overview

From MVA005 to Control unit: (DIRECTION-1: TRANSMIT DATA - FROM ACT to RCU)

From Control unit to MVA005: (DIRECTION-2 RECEIVE DATA - FROM RCU TO ACT)

Further details can be found on http://www.enocean-alliance.org .  

Description of individual functions

Pls. also refer to the officially published EEP A5-20-06 description and Table 8.1

Setpoint Selection (SPS)

DIRECTION-2.

Selection whether A5-20-06 and the actuator is used with Valve Position (Controller running in the room or building control system) or with its internal temperature control loop.

Operating mode (SP)

DIRECTION-2.

Setpoint Temperature °C:

The controller transmits the temperature setpoint for the internal controller (0 ... + 40°C, DB3.0 ... DB3.7 = 0 ... 80). The use of a separate, external room temperature sensor is recommended whose room temperature (DB2.0 ... DB2.7) is transmitted to the drive by the room controller as part of the A5-20-06 protocol. The internal controller thus does not use the ambient temperature measured in the near field of the radiator, but the actual room temperature. When operating with an internal temperature sensor, DB2.0 ... DB2.7 must be set to 0x00. Every values not equal to zero (0x00) is interpreted as a valid room temperature value and thus will be used and potentially result in faulty control behavior.

Valve position %:

The controller transmits 0 ... 100% (DB3.0 ... DB3.7 = 0 ... 100) and converts it into an actuating movement by the actuator (0% = closed valve / 100% = completely open valve).

Local offset (LO)

DIRECTION-1.

The MVA005 local offset (LO) function offers a convenient way for end users to request temperature changes locally at the actuator/radiator while the room control unit may be out of reach or may not be accessible at the time of the desired temperature change. Nevertheless, LO follows a master (control unit) and slave (MVA005) structure, which requires the control units to confirm any local change with corresponding data sent to the respective actuator device.

Setpoint Temperature °C:

Local changes of +/- 1°C … +/- 5°C will be transmitted to the control unit as absolute °C value calculated from the effective setpoint, plus or minus the desired °C value change. Example: Setpoint controller = 21°C + 2°C local offset change = 23°C transmitted value.

Valve position %:

Local changes of +/- 1°C … +/- 5°C will be transmitted to the control unit as relative value.

Radio communication interval (RFC)

DIRECTION-2.

The 4BS radio communication interval of the actuator can be freely determined within the EEP specified range by the room controller. This allows to e.g. reduce radio traffic and power consumption when outside of the heating times (e.g. overnight, absence, setback mode), while in heating periods the response times of the drive can be shortened. In default “auto” setting, the drive uses and varies between 2, 5 and 10 minutes based on its internal flow temperature sensor. (2 minutes at T flow> 50 ° C, 5 minutes at T flow> 45 ° C, otherwise 10 minutes). Continuous operation with a radio interval of less than 5 minutes leads to increased energy consumption and faster discharge of the internal storage. Short radio intervals must be coordinated with the available flow temperature and heating times. If necessary, check the voltage of the internal memory by means of remote commissioning.

SIGNAL telegram cycle time can also be changed within the specified range through Remote Commissioning. Pls. refer to the DDF and Section 9.5.

Summer bit (SB)

DIRECTION-2.

The actuator receives the status bit summer mode from the external controller through Standard 4BS message. The valve closes while the radio communication interval is increased to once every 8 hours. It is possible to wake up the iTRV through any local control setting. The actuator executes and transmits the local change and continues with normal operation (unless the controller does transmit the summer bit again).

Summer operation and SPS:

• SPS = 0 (default valve position): As in normal operation, the default position [0 ... 100%] is set

• SPS = 1 (default temperature setpoint): When summer mode is activated, the control is frozen and the last valve position is retained.

Summer operation and reference run:

• The 4BS command "REF" can also be used in summer operation. After the 8h interval has elapsed, REF = 1 triggers a soft reset with subsequent reference travel and 4BS communication. In the context of 4BS communication, the REF bit or the SB bit can be reset immediately.

Summer operation and valve detection:

• The valve detection, which checks the correct assembly on the valve every 6 weeks (8.2.7), also takes place in summer operation.

Standby bit (SBY)

DIRECTION-2

When used in permanently unheated rooms, the actuator's internal energy storage cannot be recharged, a condition that must be avoided. If operation under such conditions cannot be avoided, then the use of the standby mode is recommended. The radio communication is stopped and the storage consequently only discharges very slowly. In order to reactivate the drive from standby, it is sufficient to operate it locally on its dial. As an alternative to standby, there is the option of increasing the radio interval from typically 10 to 60 minutes. The unit remains accessible via radio. By setting the summer bit SB (8.2.5), the radio interval can even be extended to 8 hours; the drive can also be addressed via radio.

Standby and valve detection:

• The valve detection, which checks the correct assembly on the valve every 6 weeks, also takes place in standby.

Freeze protection

The freeze protection function periodically checks the temperature of the flow sensor and opens the valve 95% when the temperature falls below 6ºC in order to prevent the water in the system from freezing (and thus serious damage to the building).

• Special case target temperature 0ºC: If the target temperature of the control is 0ºC, the freeze protection does not take effect at <6ºC, but only at <0ºC.

• Standby: In standby, the valve is closed regardless of a communicated setting position, the freeze protection also opens here to 95% at temperatures below 0ºC.

• Installation position: In the installation position the actuator is deactivated, the valve is completely open. Freezing of the system is therefore impossible.

Radio strength and com. error (RSS & RCE)

DIRECTION-1

With RSS, the actuator provides information about the signal strength measured by the internal receiver. If RSS is set, its radio signal from the room controller is weak. However, stable radio communication is not necessarily ruled out. Received telegram signal strength of <-80dBm will set the RSS bit. RCE (Radio communication error) is used to signal radio loss following 6 consecutive missing data telegrams from the control unit to the valve actuator. In case of RCE, the RSS bit will also be set.  

Reference Run (Maintenance)

By setting the REF bit, the drive executes a reference run including a 0%-point recalibration and restarts. The communication interval is set to 2 minutes (maintenance interval) for the next 30 minutes and the (uncorrected) ambient temperature measured at the drive is transmitted. When the 30 minutes have elapsed, the temperature approximation and smoothing restarts. 21 ° C are set as the default temperature setpoint, but they are overwritten by the first valid telegram of the room controller.   

Radio telegram example

DIRECTION-1 MVA005 to Control unit /Gateway

DIRECTION-2 Control unit / Gateway to MVA005

Further details can be found on http://www.enocean-alliance.org .