domat UC905 User manual

domat UC905 08/2018 Subject to technical changes. 1
UC905
Room unit for controller FCR015
Summary
The UC905 room unit is a communicative human-machine interface for VAV unit
controller FCR015.
According to production type, each version of the unit may contain display, backlight
and knob.
UC0905 –basic version with display and knob
UC905BL –version with display, knob and backlight
UC905DK –version without knob and display
The UC905 is successor of UC095 room unit and can be used with controllers
FC015 and FCR015. Beware of unit terminals connection. It differs from its
predecessor.
Application
▪VAV systems –measurement and control of room temperature and CO2
concentration.
Function
The unit reads room temperature, humidity and CO2concetration in the room air,
temperature correction / setpoint by a knob, and required operation mode which is set
by a short push or in the menu. Data is transmitted to the room controller. The main
controller, FCR015, may send to the unit other data (heating / cooling mode, fan stage,
day / night / standby mode etc.) which are displayed on the LCD display.
Connect the room unit to FCR015 over a 4 core cable, the most suitable types are JY(St)Y
or LAM 2x2x0.8. Use the same type which powers the FCR015 controller as if the room
unit power is taken from the FCR015 terminals, the cores in a terminal should be of the
same cross-section.
If there is communication failure between UC905 and FCR015, there is a wrench and
alarm bell icon at the UC905 display. Check signal polarity (terminals 8, 9), bus
termination, and correct wiring at the FCR015 side (see FCR015 data sheet).
Technical data
Power supply
24 V AC +/- 20%
Consumption
3 W
Galvanic isolation
1 kV

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Communication
RS485, Modbus RTU,
selectable speed 1200 ... 115200 bps
SW
ModComTool
Temperature measuring range
-20 ÷ 70 °C (accuracy ±1 ˚C)
Humidity measuring range
10 ÷ 90 rH (accuracy ±3 % rH)
CO2concetration measuring range
NDIR technology, range 0-5000 ppm, measuring
accuracy (operating conditions 0-45 °C, relative
non-condensing humidity 0 to 85%) ± 50 ppm ±
3% of measured value, CO2 reaction time (90%)
90 s
Setpoint
as configured, +/- 10 to +/- 1 K
Display
LCD 60 x 60 mm
Terminals
screw terminals for wires 0,14 –1,5 mm2
Cover
ABS, RAL9010, other colours
Protection
IP20
Dimensions
90x115x30 mm
Ambient temperature
External conditions: -5 –45 °C; 5 – 95 % relative
humidity; non-condensing gases and chemically
non-aggressive conditions (according to EN
60721-3-3 climatic class 3K5
Storage: -5 –45 °C; 5 – 95 % relative humidity;
non-condensing gases and chemically non-
aggressive conditions (according to EN 60721-3-1
climatic class 1K3)
Standards conformity
EMC EN 61000-6-2 ed.3:2005, EN 61000-6-4
ed.2:2006 + A1:2010 (industrial environment)
Electrical safety EN 60950-1 ed.2:2006 +
A11:2009 + A12:2011 + A1:2010 + A2:2014 +
Opr.1:2012 + Z1:2016
Hazardous substances reduction EN 50581:2012
Terminals
1
2
3
4
5
6
7
8
9
1: NC not connected
2: NC not connected
3: NC not connected
4: NC not connected
5: GND technical earth (TE)
6: G0 power –common point
7: G power
8: K- communication, RS485 –
9: K+ communication, RS485 +

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DIP switches
Back of the PCB
BUS END: if ON, the bus is terminated (if last
device on the line)
USR: not used, reserved for future
applications
INIT: setsthe controller into default state and
sets bus address to 1, baud rate to 9600.
To init, proceed as follows:
-connect the device over RS485 to a
PC with ModComTool config tool
-set INIT to ON
-apply power (use only the connector
without bottom)
-find the controller in the tool (Scan)
-set INIT to OFF
-in the ModComTool, open the
controller window
-click the Init button in the tool
-remove and apply power.
Installation
Units are intended for operating in a normal and chemically non-aggressive
environment. They do not need any servicing or maintenance. Install them in a vertical
position at places where they can be operated easily and measure correct values of
temperature, i.e. in the height of about 150 cm, with no direct sunlight or other heat /
cool source (AHU outlets, refridgerator, electrical appliances). The device consists of
two parts: bottom with screw terminal block and cover containing PCB, display, and the
knob. The bottom part is fixed by 2 or 4 screws to any flat surface or a flush-mounting
box Ø 50 mm. At the back of the bottom there is an aperture for cabling. The bottom
should be installed and cabling connected first, and the upper part inserted after the
construction works have been finished to prevent damage to the unit.
Seal the conduits to avoid influencing the sensor by draught. Use insulating pad when
installing the sensor on cold walls. Avoid sensor exposition to sunlight or other heat
sources.
Cover opening
When removing the display part, proceed as follows:
-press gently the side parts of the unit and pull the right of the display part by
several milimeters
-pull the left of the display part

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-pull the display part and remove it from the bottom.
Do not bend the display part too much, the connector pins could be damaged. The locks
are only at the sides of the display part, not at the top nor bottom.
Display
A large (60 x 60 mm) display clearly shows
actual room temperature and controller status
with 7-segment digits and standard Day, Night,
Off, and Time scheduler symbols. Active output
is indicated by a heating symbol. In the upper
part, there are week days used for time
scheduler setup. Other symbols are not used.
LCD symbol set

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Dimensions
UC905
UC905DK
All dimensions in mm.
Safety note
The device is designed for monitoring and control of heating, ventilation, and air
conditioning systems. It must not be used for protection of persons against health risks
or death, as a safety element, or in applications where its failure could lead to physical
or property damage or environmental damage. All risks related to device operation
must be considered together with design, installation, and operation of the entire
control system which the device is part of.

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Changes in
versions
10/2017 –The first datasheet version.
08/2018 –Minor changes.