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IntroductIon

The CMa10/CMa11 is a 2-way M-Bus communicating temperature and 
humidity sensor for indoor use.   
For a complete description of the product or for information in Swedish, 
visit the Elvaco AB website, www.elvaco.com.

overvIew

CM

a

10

/

11

Indoor M-Bus temperature and humidity sensor

1.  Push-button (SW2) (CMa10)

2.  Display (CMa10)

3.  Push-button (SW1)

4.  M-Bus in

5.  Serial number (secondary 

address) 

6.  Do not use for mounting

mountIng

When mounting the CMa10/CMa11, avoid rooms with a lot of 
supplementary heat, such as kitchens or south facing rooms. Position 
the sensor away from direct sunlight. Avoid placing on an external wall 
or near an external door. Make sure that the sensor is not positioned 
closer than 1 m from the nearest radiator and at least 1.5 m above the 
floor. The CMa10/CMa11 can be mounted directly on the wall, or over a 
mounting box. If the CMa10/CMa11 is placed over a conduit pipe, it is 
recommended to fill the pipe to prevent air flow.

Remove the rear cover to connect the M-Bus 2-wire interface.

ImPortAnt

• 

Do not use mounting holes (6) as shown in overview.

• 

If the product should be demounted from the wall, use a 
screwdriver to separate the product from the rear cover. The 
screwdriver should be inserted carefully in the upper part of the 
holes.

m-Bus 2-wIre Bus

M-Bus is a multi-drop 2-wire bus with no polarity. Use a cable of area 
0.25-1.5 mm

2

, e.g. a standard telephone cable (EKKX 2x2x0.5).  

Demount the M-Bus terminal (4) by sliding the terminal to the right. 
Connect the incoming wiring to the terminal and slide back in position.

ImPortAnt

 

• 

All connected M-Bus slave devices must have unique M-Bus 
secondary or primary addresses depending on addressing mode.

• 

Measure voltage over M-Bus slave connection to verify M-Bus 
master connection. Voltage should be between 21-42 VDC.

confIgure usIng lcd dIsPlAy (cmA10)

The display shows current sensor information and is also used to 
change and view the CMa10 configuration, i.e. M-Bus primary and 
secondary addresses. End users only have access to the Standard 
menu. The Setup menu can only be entered using the push-button SW1 
on the rear of the product. 

standard menu 

Push-button SW2 on the front is used for changing display page, 
resetting received messages and average values which can be viewed 
by the end user. Enter next page by pressing push-button SW2.

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