catrone
Temperature Controller with
comprehensive run-time self-supervision
Prog. mode
Stage 1
Stage 2
Blocked
Hand
APPLICATION
MDT-2000 is a temperature controller (digital ther-
mostat), which is intended for controlling stage
burners in combustion plants. The controller is also
suitable for controlling heating pumps, electric ele-
ments in ventilation plants etc.
FUNCTION
MDT-2000 measures the outgoing water tempera-
ture from a heating boiler with a temperature sen-
sor. The controller has two set limits for disconnec-
tion of power stages with associated temperature
hysteresis.
If there is no 230 VAC signal connected to terminal
3, the controller is blocked. Terminal 5 and 6 respec-
tive terminal 8 and 9 are connected to each other via
relay contacts.
If permission to operate is given, i.e. a 230 VAC sig-
nal on terminal 3, and the temperature is below set
value for "Stage 1 OFF" minus the temperature hys-
teresis for stage 1, the first relay switches, breaks
connection between terminal 5 and 6 and connects
terminal 4 with 5. When the temperature exceeds
"Stage 1 OFF", the first relay switches back, breaks
connection between terminal 4 and 5 and connects
terminal 5 with 6.
During permission to operate, if the temperature
falls below value for "Stage 2 OFF" minus the tem-
perature hysteresis for stage 2, the second relay
switches, breaks connection between terminal 8
and 9 and connects terminal 7 with 8. When the
temperature exceeds "Stage 2 OFF", the second re-
lay switches back, breaks connection between ter-
minal 7 and 8 and connects terminal 8 with 9.
MDT-2000 can also be operated manually using the
hand operation.
SELF-SUPERVISION
MDT-2000 monitors the measuring signal from the
temperature sensor to be within the measuring
range of 0...150 °C.
®
0083
°C
PGM
ESC
Hand
Operating and installation manual
Dok.nr: Mi-229gb / 2006-02-09
If the measuring signal is outside the measuring
range the operation is blocked and the display start
to flash "- - - -", relays switch-over and terminal 5
and 6 with terminal 8 and 9 closes.
The run-time self-supervision stops the operation
under the following circumstances:
q No temperature sensor is connected
q Faulty connected temperature sensor
q Short-circuit in the temperature sensor
q Break inside the temperature sensor
q Malfunctioning wiring between the temperature
sensor and MDT-2000
MDT-2000 returns to normal operation as soon as
the measuring signal is within the measuring range
again.
DESIGN
MDT-2000 is equipped with three connected printed
circuit boards, I/O-board, sensor-board and dis-
play-board. The display-board consists of a 4-digit
indicator, 6 LED's for indication and 4 keys for pro-
gramming. The enclosure is of ABS plastic and pro-
vided with four threaded holes for cable fittings. For
fitting on DIN-rail a mounting kit is used. MDT-2000
can be programmed without opening the enclosure.
INSTALLATION
MDT-2000 is mounted via 4 screws, max Æ4 mm.
The location of the holes is shown back of the enclo-
sure. Do not place the unit on a warm surface.
Connect power supply according to the electrical
connection. Check that the controller is marked with
the correct power supply voltage. If using cable
glands without a nut on the inside, glands with
grommet must be used to avoid damage to the
threads on the enclosure. Remember to remove the
transparent protective cover from the front panel af-
ter finished installation.
INSTALLING THE TEMPERATUR SENSOR
The temperature sensor can be connected with two
or four wires. The best result is received with a
4-wire connection. A 2-wire connection is easier to
install but results in a risk for measurement error in
connections with long wires.
2
Ex. a 10m 2x0,25 mm
measurement with approximately 3,5 °C. Shielded
cable is recommended.
MDT-2000
Cu-cable gives an error in
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