ABB Comem DTI User manual

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TRANSFORMER COMPONENTS
Temperature monitoring device
Comem DTI and Comem eDTI
Instruction manual
Content
1. Safety
1.1 Safety instructions 3
1.2 Specified applications 4
1.3 Safety notes on the equipment operation 4
2. Comem DTI and eDTI 5
2.1 Operating principle 5
2.2 Installation 6
2.3 Connection of the temperature sensors 7
2.4 Output relays 7
3. Electrical diagram 8
4. Wiring connection 9
5. Front panel description 10

2TEMPERATURE MONITORING DEVICE COMEM DTI AND COMEM EDTI - INSTRUCTION MANUAL
6. Programming of the device 11
6.1 Selection of the HOLD function 11
6.2 Selection of the number of active inputs 12
6.3 Control ventilation 12
6.4 Selection of the threshold of switch on and switch off
ventilation 13
6.5 Selection of the alarm and trip threshold 13
6.6 Selection of address network identification for the
communication of the serial port (MODBUS-RTU protocol) 14
6.7 Selection of the baud rate 14
6.8 Selection data bit and stop bit 15
6.9 Selection of the linked channel with the analogue output 16
6.10 Configuration output signal 17
6.11 Configuration diagnostic probes 18
6.12 Exit from the programming phase 18
7. Modality of tripping and restore 19
7.1 Alarm 19
7.2 Trip 19
7.3 To silence alarm 19
8. Diagnostic 20
9. Visualization of the maximum measured temperature 21
10. Visualization of the channels with the higher temperature 22
11. Test of the light signaling 22
12. Exclusion of the input probes not used 22
13. Technical features 23
14. Dimensions 24
15. Movement, transport and storage 25
16. Appendix A: MODBUS address. 26

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TRANSFORMER COMPONENTS
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1. Safety
1.1 Safety instructions
Make sure that any persons installing, taking into operation and
operating the “temperature monitoring device Comem DTI/eDTI”:
• Are technically qualified and competent.
• Fully comply with these assembling instructions.
Improper operations or misuse could cause danger to:
• life and limb.
• to the equipment and other assets of the operator.
• to the equipment proper function.
Opening of the device will void your warranty.
Safety instructions in this manual are shown in three different
forms to emphasize important information.
THIS INFORMATION INDICATES PARTICU-
LAR DANGER TO LIFE AND HEALTH. DISRE-
GARDING SUCH A WARNING CAN LEAD TO
SERIOUS OR FATAL INJURY.
ALL RELEVANT FIRE PROTECTION REGULA-
TION MUST BE STRICTLY OBSERVED.
THIS INFORMATION INDICATES PARTICU-
LAR DANGER TO EQUIPMENT OR OTHER
PROPERTY OF THE USER. SERIOUS OR FA-
TAL INJURY CANNOT BE EXCLUDED.
THE TEMPERATURE CONTROL UNIT
COMEM DTI/EDTI MUST NOT BE INSTALLED
NEAR SOURCES OF ELECTROMAGNETIC
INTERFERENCE.
INSTALLATION, ELECTRICAL CONNECTION
AND FITTING THE DEVICE MAY ONLY BE
CARRIED OUT BY QUALIFIED PERSONNEL
AND ONLY IN ACCORDANCE TO THIS IN-
STRUCTION MANUAL.
IT IS RESPONSIBILITY OF THE USER TO
MAKE SURE THAT THE DEVICE IS USED FOR
SPECIFIED APPLICATION ONLY.
FOR SAFETY MATTERS, PLEASE AVOID ANY
UNAUTHORIZED AND IMPROPERLY WORKS.
THESE NOTES GIVE IMPORTANT OR
SPECIFIC INFORMATION CONCERNING THE
EQUIPMENT OR AS TO WORK WITH THE
EQUIPMENT.
WARNING
WARNING
CAUTION
CAUTION
CAUTION
NOTE

4TEMPERATURE MONITORING DEVICE COMEM DTI AND COMEM EDTI - INSTRUCTION MANUAL
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1. Safety
1.2 Specified applications
The Temperature monitoring device Comem DTI/eDTI is used in
resin or dry type transformers and can also be easily adapted for
use in oil transformers. The Comem DTI/eDTI uses PT100
temperature probes for a constant monitoring of transformer
temperatures. The device generates two intervention levels of
electric signals (alarm and trip).
1.3 Safety notes on the equipment operation
The electrical installation must conform to the national safety
regulations.
The Temperature monitoring device Comem DTI/eDTI has double
insulation. Earthing is not required.
THE WIRES MUST BE FIXED PROPERLY
CAUTION

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TRANSFORMER COMPONENTS
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2. Comem DTI and eDTI
2.1 Operating principle
The Comem DTI family are devices which use PT100 temperature
probes for constant monitoring of transformer temperatures in 4
points: three on the transformer winding columns and one on the
machine's magnetic circuit.
If the transformer malfunctions, causing its temperature to rise,
Comem DTI unit generates an alarm signal. If the temperature
reaches danger levels the unit generates a second intervention
level. Moreover, a switch can manage the fan.
Comem eDTI version has one port of serial communication RS485
which allows the connection of the measurement data, control
and programming of the device to acquisition system (PC, PLC,
SCADA, etc.). Modbus RTU is the protocol used (see specific
manual for instruction).
A Windows software is available for a management of the device
with complete function of control, storing data and recording
alarm. In addition, it is available an analogue settable output 0-20
mA or 4-20 mA with scale FROM -30°C to +200°C.
The devices type Comem DTI and Comem eDTI allow the control
and the visualization of temperature read with probe type RTD
PT100.
For each channel of measure are available two levels (alarm and
trip) that actives the commutation of the relative output relay for
signaling at distance or for disabling the machine under control.
In the front panel there are a double three-digit display that
shows the temperatures, the status of the alarm of the
measurement channels and five buttons for the programming.
The instrument can control the ventilation, storing maximum
values and trip alarms.

6TEMPERATURE MONITORING DEVICE COMEM DTI AND COMEM EDTI - INSTRUCTION MANUAL
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2. Comem DTI and eDTI
2.2 Installation
The Comem DTI family are devices which use PT100 temperature
probes for constant monitoring of transformer temperatures.
Read carefully the present manual before to install and to use the
device. The device must be installed and used by personal
opportunely learned.
Before to proceed at the installation it’s necessary to verify if the
device is intact and it hasn’t damages due to transportation or
handling. The power supply must be compatible with the device
range. The instrument installation must be done in total absence
of voltage and observing the security norm in force.
All operation of maintenance and reparation executed by not
authorized persons are forbidden.
If during the functioning the device becomes unsafe, it’s
necessary to put it out of action and to be sure that this device
won’t be used unintentionally.
The use shall be considered unsafe when the instrument:
• doesn’t work regularly
• has damage clearly visible
• has damage caused of transport or handling
• is stored in bad condition

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TRANSFORMER COMPONENTS
2.3 Connection of the temperature sensors
For the connection of the sensor RTD PT100 it’s necessary to
follow the indication of the wiring diagram of this manual: pay
attention to not invert the position between the conductors with
red insulator and the conductor with white insulator. The probes
type PT100 with three wires use the third wire to compensate the

If the sensor has two wires (normally white and red) it’s necessary
to short-circuit the terminals with the red wire (1-2, 4-5, 7-8, 10-11).
To reduce the external noises, it’s necessary to use the following
indication for the wires:
• use probes with shielded wire connected at earth and wires
twisted
• separate the wires of the probes from wires of power supply
• use wires with section at least of 0,5 mm2
• use wires with conductor with tin or silver-plated
2.4 Output relays
For the connection of the output contacts it’s necessary to follow
the indication in the diagram.
The ALARM and TRIP relays commute when the threshold set
value gets over. The FAULT relay is normally energized, and it
commutes in presence of a PT100 anomaly or of the device.
During the normal functioning of the device the contact 38-39 is
open, while the 39-40 is closed.
The FAN relay is used to control the cooler fan, according to the
on/off thresholds set.

8TEMPERATURE MONITORING DEVICE COMEM DTI AND COMEM EDTI - INSTRUCTION MANUAL
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3. Electrical diagram

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TRANSFORMER COMPONENTS
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4. Wiring connection
View rear panel of the instrument with terminals for the connections

10 TEMPERATURE MONITORING DEVICE COMEM DTI AND COMEM EDTI - INSTRUCTION MANUAL
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5. Front panel description
1
2
3
4
8
910 10
11
7
6
5
Legend:
1. LEDs T1-T2-T3-T4 for the on-measuring channel displayed
2. T1-T2 and T3-T4 displays for the channel temperature
visualization and settings
3. LEDs ALARM for the Alarm status in the related channels
(1 to 4)
4. LEDs TRIP for the Trip status in the related channels (1 to 4)
5. LED FAULT: failure indication (device or PT100 probes)
6. LED HOLD: the manual reset is active
7. LED FAN: the ventilation output is active
8. Push - button HOT / T. MAX to display the measured channel
with higher temperature (LED indication activated) and to
display maximum temperatures achieved
9. Push - button ENTER / RESET to confirm programming set
and the manual alarm reset intervention
10. Push - buttons  for selecting the displayed channel
and for changing parameter of programming
11. Push - button SET for the settings

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TRANSFORMER COMPONENTS
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6. Programming of the device
When the device is switched on, on the display will flash the index
of the internal software: later the device starts to display the
temperature read on the measured input.
To enter in the programming mode, press the button SET for
some second up to light the relative SET LED.
The settings appear in the sequence showed after (6.1, 6.2, etc).
To go out of the programming mode without changing the preset
values, it’s necessary to press SET without confirming with the
ENTER key the modified data.

keys and the ENTER key to store the modification.
The pressure of the ENTER key move automatically the
programming at the successive function or value.
6.1 Selection of the HOLD function
This is the first function in the set menu. In this programming
phase the HOLD LED switches on.
The Hold function allows to store the alarm condition that can be
rearmed only manually with the RESET button when the
temperature is lower than the threshold set.
If this function is disabled it’s possible to rearm the ALARM with
the RESET button even if the temperature is higher than the
threshold set, while the value of temperature come back under
the threshold set the alarm will be automatically deleted.

• ON function enabled
• OFF function disabled
Press the ENTER key to confirm the operation.
HOLD mode  
HOLD mode deactivated HLD Off

12 TEMPERATURE MONITORING DEVICE COMEM DTI AND COMEM EDTI - INSTRUCTION MANUAL
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6. Programming of the device
Active inputs mode  
 Ch 
All inputs activated Ch ALL
  
Fan control inhibited FAN Off
 FAN ON
  
Fan control inhibited FAN Off
 FAN ON
 FAN 
6.2 Selection of the number of active inputs
It is possible to select the number of activated inputs. It’s
possible to choose between 3 and 4 inputs enabled; if there are 3
inputs enabled the T4 display remain off.

Confirm with ENTER.
6.3 Control ventilation
The FAN led will switch on indicating the programming of the
ventilation control.
If 3 inputs are selected the following setting are available:
• ventilation control inhibited
• fan control active on 3 inputs

Confirm with ENTER.
If 4 inputs are selected the following setting are available:
• ventilation control inhibited
• fan control active on 3 inputs
• control active only on fourth input

Confirm with ENTER.

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TRANSFORMER COMPONENTS
6.4 Selection of the threshold of switch-on and
switch-off ventilation
It is possible to program the threshold for enabling and disabling
the ventilation.
• Selection the threshold for disabling ventilation
The FAN LED is on, with fixed light indicates this phase of

temperature indicated on display. Interval of programming:
from -25°C up to (enabling threshold - 1°C)
Confirm with ENTER.
• Selection the threshold for enabling ventilation
The FAN LED is on, with flashing light indicates this phase of

temperature indicated on display. Interval of programming:
from (disabling threshold + 1°C) up to 200°C
Confirm with ENTER.
6.5 Selection of the alarm and trip threshold
The FAN This setting starts to program from the channel number 1.
The ALARM LED ON indicates the programming of the alarm:

Interval of programming: from -25°C up to (trip threshold -1°C)
Confirm with ENTER.
The TRIP LED ON indicates the programming phase of the
tripping threshold.

Interval of programming: from (alarm threshold + 1°C) up to 200°C.
Confirm with ENTER.
Repeat the same operation for the successive channels.

14 TEMPERATURE MONITORING DEVICE COMEM DTI AND COMEM EDTI - INSTRUCTION MANUAL
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6. Programming of the device
Baud rate setting  
 BDR 
 BDR 
 BDR 
 BDR 
6.6 Selection of address network identification for
the communication of the serial port
(MODBUS-RTU protocol)
6.7 Selection of the baud rate
THIS SETTING IS SIGNIFICANT ONLY FOR
COMEM EDTI MODEL.
THIS SETTING IS SIGNIFICANT ONLY FOR
COMEM EDTI MODEL.
NOTE
NOTE
This setting is indicated on displays with:
• value to set on T1-T2 display
• ID on T3-T4 display.

The range for accepted value is from 1 to 247.
Confirm with ENTER.
This setting is indicated on displays with:
• BDR on T1-T2 display
• value to set on T3-T4 display.

It’s possible to choose between the following values: 2,4 - 4,8 - 9,6
19,2 kbps.
Confirm with ENTER.
Modbus setting  
Setting address MODBUS network  ID

15
TRANSFORMER COMPONENTS
Data-stop bit setting  
 NO 
 NO 
 EVE 
 ODD 
6.8 Selection data bit and stop bit
THIS SETTING IS SIGNIFICANT ONLY FOR
COMEM EDTI MODEL.
NOTE
This setting is indicated on displays with:
• the type of parity on T1-T2 display
• the number of data bit and stop bit on T3-T4 display.

Confirm with ENTER.

16 TEMPERATURE MONITORING DEVICE COMEM DTI AND COMEM EDTI - INSTRUCTION MANUAL
6.9 Selection of the linked channel with the
analogue output
THIS SETTING IS SIGNIFICANT ONLY FOR
COMEM EDTI MODEL.
NOTE
This setting is indicated on displays with:
• AN on T1-T2 display
• the linked measure channel on T3-T4 display: CH 1/2/3/4 for the
1/2/3/4 measure channel, ALL to link the measure channel with
the higher temperature.

Confirm with ENTER.
Link channel setting  
Channel with higher temperature AN ALL
 AN 
 AN 
 AN 
 AN 
—
6. Programming of the device

17
TRANSFORMER COMPONENTS
6.10 Configuration output signal
THIS SETTING IS SIGNIFICANT ONLY FOR
COMEM EDTI MODEL.
THE MAXIMUM LOAD FOR ANALOGUE

NOTE NOTE
In this phase it’s possible to define the type of signal of analogue
output as 0-20 mA or 4-20 mA.
This setting is indicated on displays with:
• AN0 -20 to set the output as 0-20mA or (0 mA = -30°C;
20 mA = 200°C)
• AN4 -20 to set the output as 4-20 mA or (4 mA = -30°C;
20 mA = 200°C)

Confirm with ENTER.
  
  
  
 AN 
 AN 
 AN 

18 TEMPERATURE MONITORING DEVICE COMEM DTI AND COMEM EDTI - INSTRUCTION MANUAL
—
6. Programming of the device
6.11 Configuration diagnostic probes
This function allows to enable or to disable the control on the
probes. This functionality controls the variation of the
temperature in a defined time. A flag raise if this variation is
higher than a set value.
6.12 Exit from the programming phase
Press the SET key or wait for about 8 seconds without to press
any key to come out of the programming phase.
It’s necessary to indicate the maximum variation temperature:
• FDC: min 5°C or max 30°C
and after the time in which to do the control:
• FDC: min 10” or max 90” (time in seconds)

decrease.
Confirm with ENTER.
FDC setting  
FDC mode disabled FDC Off
FDC mode enabled FDC ON
Temperature configuration FDC  
Min °C FDC 
Max °C FDC 
Time configuration FDC  
Min in seconds FDC 
Max in seconds FDC 

19
TRANSFORMER COMPONENTS
—
7. Modality of tripping and restore
7.1 Alarm
On the relative channel, if the threshold value set is exceeded of
+1°C, after 5 seconds the ALARM relay is energized and the ALARM
led is.
The alarm rearm (relay de-energized and the involved LED off)
occurs when the temperature goes down of 2°C respect at the
threshold value set.
7. 2 Trip
On the relative channel, if the threshold value set is exceeded of
+1°, after 5 seconds the TRIP relay is energized and the TRIP led is.
The trip rearm (relay de-energized and the involved LED off)
occurs when the temperature goes down of 2°C respect at the
threshold value set.
7.3 To silence alarm
If the Hold function is disabled, it’s possible to silence the alarm
condition. During the alarm condition the ALARM relay and the
“ALARM” optical signalling are enabled.
Pressing the Reset button, the relay will be de-energized while the
optical signalling of the alarm condition becomes flash.
If the temperature increases up to reach the (TRIP temperature - 1°C),
the relay and the optical signalling are enabled another time.
If after the reset, the temperature goes down under the threshold
value set, the flashing optical signalling will be automatically
deleted.

20 TEMPERATURE MONITORING DEVICE COMEM DTI AND COMEM EDTI - INSTRUCTION MANUAL
—
8. Diagnostic
The device is provided of the thermic probes diagnostic function.
The condition controlled on the measured input are:
• Probe PT100 interrupted: signalling on the display the message
O P E (open).
• Probe in short circuit: signalling on the display the message S H
R (short circuit).
• Probe out of order for wrong read temperature: signalling on
the display the message F D C.
When the device switches on the auto-diagnostic, FAULT relay
commutes and it remains in the energized status until one of the
above-described conditions appears, or if a device failure occurs,
or if the power supply is absent.
The anomaly conditions are signalled also by the FAULT led on.
Every time that a probe is out of order because it is interrupted
(OPE) or in short circuit (SHR) or the delta of temperature is too
elevated (FDC), the corresponding channel LED flashes until the
anomaly stop.
The alarm of interrupted probe (SHR) or open probe (OPE) will be
reset automatically while the alarm for the delta of temperature
(FDC) disappears by pressing this sequence:
• push the ENTER key
• keep it pressed
• 
The status of the relay contact (all available with exchange
contact) is showed in the following table:
RELAY DISABLE STATUS ENABLE STATUS UNPOWERED STATUS
ALARM   
TRIP   
FAN   
FAULT   