TECSYSTEM NT538 User manual

http://www.tecsystem.it
INSTRUCTION MANUAL
TECSYSTEM S.r.l.
Via Cristoforo Colombo, 5/C
20094 Corsico (Milan)
phone [phone]
Fax: [phone]
NT538 P8 V4-R1.4 protection relays
TECSYSTEM S.r.l ®
R.1 08/09/05
NT538
Cross Reference RA Part Number PP8704

2NT538 P8 V4-R1.4 protection relays
TECSYSTEM S.r.l ®
INNOVATIONS INTRODUCED WITH THE NT538
1. New hardware and software for a further improvement of immunity to disturbances.
2. Reading rate increasing, indispensable for applications where fast temperature
variations must be monitored.
3. Intelligent control of alarm detecting relays which is able to exclude possible
overtemperatures caused by an external disturbance without causing working prob-
lems or manual reset conditions.
4. Detecting of possible corruption of data stored in the memory (Ech) and default
value reset for security.
5. Storage in T. Max mode of possible alarms occurred from last reset and recording of
possible sensor failures.
6. Error detecting in case of wrong programming with specific indication of the wrong
value couple.
7. Possibility to return to previous programming step for a faster value modification.
8. Safer programming block which can be activated just through the closing of an inner
jumper.
9. SCAN display mode to see, in sequence, the temperature and the state of the
alarms for all channels
10. 8 channels with two programmable thresholds in an independent way.
11. Fan contact to check a cooling system.
12. More compact sizes compared with T538 version1.
13. Options with serial output to control the expansion module such as:
a) EXT 4.20-8: module with 4-20 mA outputs for each channel
b) EXT RL-8: module with 2 relays (alarm and trip) for each channel
c) EXT RS485 Modbus: module for connection on a Modbus network
14. Possibility to connect many expansion module on serial output in order
to have many expanding options simultaneously.

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NT538 P8 V4-R1.4 protection relays
TECSYSTEM S.r.l ®
1) TECHNICAL SPECIFICATIONS
POWER SUPPLY
• Rated values 24-240 Vac-dc
• Highest tolerable values 20-270 Vac-dc
• Vdc with reversible polarity Vdc
COMMUNICATION
• option
INPUTS
• 8 inputs RTD Pt100—3 wires
• Removable rear terminals
• Input channels protected against electro-
magnetic noises and spikes
• Sensor length cable compensation up to
500 m (1 mm² )
OUTPUTS
• 2 alarm relays (ALARM-TRIP)
• 1 alarm relay for fan control (FAN)
• 1 alarm for sensor fault or working anom-
aly (FAULT)
• Outputs contacts capacity: 5A-250V ac
resistive.
TESTS AND PERFORMANCES
• Assembling in accordance with CE rules
• Protection against electrical noises
CEI-EN50081-2/50082-2
• Dielectric strength 2500 Vac for 1 minute
from relays to sensors, relays to power
supply, power supply to sensors
• Accuracy ± 1% full scale value ± 1 digit
• Ambient operating temperature from –20
°C to +60°C
• Humidity 90% no-condensing
• ABS self-extinguishing housing NORYL
94VO
• Frontal in polycarbonate IP65
• Absorption 3VA
• Data storage 10 years minimum
• Digital linearity of sensor signal
• Self-diagnosis circuit
• Option protection treatment of elec-
tronic part
DISPLAYING AND DATA MANAGEMENT
• 1 display 13mm high with 3 digit for dis-
playing temperatures and messages
• 8 leds to show selected channel
• 4 leds to display the state of the alarms
for selected channel
• Temperature monitoring from
0°C to 240°C
• 2 alarm thresholds (alarm/trip) for each
channel
• 2 ON-OFF thresholds for fan control
• Sensors diagnostic (Fcc-Foc)
• Data storage diagnostic (Ech)
• Programming access through front key
• Automatic output from programming cycle
after 1 minute of no-operation
• Wrong programming automatic display
• Possibility of setting automatic channels
scanning, hottest channel, manual scan-
ning
• Maximum reached temperatures, alarm
storage and sensor fault.
• Frontal alarm reset push button
DIMENSIONS
• 96 x 96 mm-DIN43700– depth 140 mm
(terminal box included)
• Panel cut-out 92 x 92 mm
SOFTWARE RELEASE
• P8 V4-R.1.4

4NT538 P8 V4-R1.4 protection relays
TECSYSTEM S.r.l ®
2) MOUNTING
Make a hole in the panel sheet with dimensions 92x92 mm.
Firmly tighten the device with the enclosed fixing blocks.
3) POWER SUPPLY
NT538 control device has an UNIVERSAL supply, i.e. it can be indifferently fed from 24 to
240 Vac-dc, regardless of polarities in Vdc.
This peculiarity is obtained using a new-concept and new-designed tested feeder, which
relieves the technician of each concern for the correct supply Vac or Vdc.
To terminal 41 must always be connected the ground.
When the control device is directly fed from secondary winding of the transformer to be
protected, it can be damaged by high-intensity over voltages.
These problems occur if the main switch is connected without load.
Above mentioned problems are much more evident when the voltage is 220 Vac is directly
taken from the transformer secondary bars and there is a fixed capacitor battery to phase
the transformer itself.
4) ELECTRICAL CONNECTIONS FOR ALARMS AND FAN
Carry out the electrical connections on the removable rear terminals, after having removed
them from the device.
ALARM and TRIP relays switch only when the set temperature limits are reached.
FAULT relay (Fault) switches when the meter is fed, while gets de-energised when a fault
occurs to Pt100 sensors, data memory fault (Ech) or when supply voltage is lacking.
FAN contact can be used to check the cooling fans or it can be inserted in a transformer
room conditioning circuit.
5) TEMPERATURE SENSOR CONNECTION
Each temperature sensor Pt100 has a white wire and two red wires (CEI 75.8 standards).
Fig. 1 shows the position inside the terminal box of monitoring unit connection cables.
Each channel can be independently programmed with two alarm thresholds (alarm and trip).
To protect the control device from line over voltages, we suggest to use the elec-
tronic discharger PT73-220, designed by TECSYSTEM S.r.l. for this specific pur-
pose.
As alternative we suggest to use supply voltages from 24 Vac or, much better, 24
Vdc.

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NT538 P8 V4-R1.4 protection relays
TECSYSTEM S.r.l ®
6) MEASURING SIGNAL TRANSFER
All the measuring signal transfer cables for Pt100 must absolutely:
• be separated from the power ones
• be made with shielded cable and twisted conductors
• have at least 0,5 mm² section
• be twisted if there is no shield
• be firmly fixed inside the terminal boxes
• have tinned or silvered conductors
All “NT” series control devices have the sensor signal linearization, with a maximum error
of 1% of full scale value.
7) TEMPERATURE SENSOR DIAGNOSTIC
In case of breaking of a temperature sensor mounted on the machine to be protected,
FAULT relay immediately switches with the relevant indication of defective sensor on the
corresponding channel.
• Fcc for short-circuited sensor.
• Foc for interrupted sensor
To eliminate the message and reset Fault switching, it is necessary to verify Pt100 con-
nections and, in case, replace the defective sensor.
8) PROGRAMMED DATA DIAGNOSTIC
In case of breaking of the internal storage or corruption of programmed data, just after
switching on, it appears Ech indication with the relevant reporting of the Fault contact.
In this case, for safety reasons, the default parameters: NCH=8, Alarm Ch1-2-3-4-5-6-7-
8= 90°C, Trip Ch1-2-3-4-5-6-7-8= 119°C, Fan= YES, Fan-on= 70°, Fan-off= 60°,
HFn= 000 are automatically loaded.
Eliminate Ech indication by pressing RESET and run programming to insert desired val-
ues.
Finally turn off and turn on again the unit to verify the correct memory working; in case it
is damaged and Ech still appears, please return the monitoring unit to TECSYSTEM for
repair.
9) TEMPERATURE DIAGNOSTIC
If one of the temperature sensor detects a temperature higher than 1°C compared to set
value as alarm limit, after approximately 5 seconds ALARM relay switches together with
turning on of channel reference LED ALARM (CHn).
When the release temperature limit is passed, TRIP relay switches together with turning
on of channel reference LED TRIP (CHn).
As soon as taken temperature returns to equal or lower values than set limit for ALARM
and TRIP relays switching, they de-energise with consequent turning off of relevant
LED’s.
TECSYSTEM S.r.l. has designed an own special cable to transfer the measur-
ing signals, according to CEI standards, with all the protection requirements
provided for : mod. CT-ES

6NT538 P8 V4-R1.4 protection relays
TECSYSTEM S.r.l ®
10) COOLING FAN CONTROL
NT538 monitoring unit, if opportunely programmed, can control ON-OFF of transformer
fans, according to set temperatures.
Fans on machine are driven using the temperatures taken from enabled channels.
11) FAN TEST
It is possible, through programming (hFn), to lay down that fans are activated for 5 minutes
each “xxx” hours, regardless of column or room temperature values (ex.: with hfn=001 fans
are activated for 5 minutes each hour).
This function has the aim to periodically verify the working of the fans and their control ap-
paratus during long idle periods.
Loading 000 value, this function is inhibited.
12) DISPLAY MODE
Pressing MODE key, display mode is loaded:
• SCAN: control device displays in scansion all activated channels (each 2 seconds)
• AUTO: control device automatically displays the hottest channel
• MAN: channel temperature manual reading of channel through cursor keys
• T.MAX: monitoring unit displays the highest temperature reached by the sensors and
possible alarm or fault situations occurred after last reset.
Select channels with
Sand T, delete values with RESET.
13) WORKING PROGRAM CONTROL
To check the programmed temperature values, shortly press PRG key. VIS indication ap-
pears for 2 seconds, confirming entering in program vision mode.
By repeatedly pressing PRG key, all the previously loaded values are rolled in sequence.
After 1 minute of keyboard no-operation, display-programming procedure will be automati-
cally left.
To end display, press ENT key.
14) LAMP TEST
We suggest to regularly carry out monitoring unit LED test.
For this operation, shortly press TEST key; all displays turn on for 2 seconds.
If one of the LED’s should not work, we kindly ask you to return the monitoring
unit to TECSYSTEM (Led RS is not available on monitoring units without optional
module)

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NT538 P8 V4-R1.4 protection relays
TECSYSTEM S.r.l ®
15) ALARM RELAY TEST
This function allows to carry out a test on relays working without having to use further de-
vices.
To start test procedure you have to keep pressed TEST key for about 5 seconds;
TST indication appears for 2 seconds, confirming entering in Relays Test mode.
Blinking led shows the relay to test; using the cursors you can select the desired one.
Press SET and RESET keys to energise and de-energise the relay to test; display will show
ON-OFF.
After 1 minute keyboard no-operation, RELAYS TEST procedure will be automatically left.
To end RELAYS TEST procedure, press TEST key.
16) ALARM RELAY EXCLUSION
If you want to exclude the ALARM signal press RESET key: relay de-energises itself and
LED ALARM, which was fixed, will start to blink.
Exclusion system is automatically disconnected when the temperature goes under the
ALARM threshold.
17) IMPORTANT NOTICE
Before carrying out the insulation test on the switchboard where the monitoring unit
is mounted, you have to disconnect it from the mains in order to avoid serious dam-
ages.
18) FRONT PANEL
Alarm
selected
channel
Display mode
Selected
channel
Message and tem-
perature display
Prg/RelaysTest
mode
Keyboard
Data
transmission
(option)

8NT538 P8 V4-R1.4 protection relays
TECSYSTEM S.r.l ®
19) PROGRAMMING
NOTE: LED PRG-ON OFF:PROGRAM DISPLAY .
LED PRG-ON ON: PROGRAM MODIFICATION
1) It is possible to return to previous step by pressing MODE key.
2) if pressing ENT it appears “ERR”, it means that one of the following mistakes has been
made: ALARM ≥TRIP or FAN-OFF ≥FAN-ON. Press PRG to return to step 1 and correct
the data.
3) After 1 minute of keyboard no-operation, programming is left without data storage.
N° PRESS EFFECT NOTES
1 PRG/SET Keep pressed PRG key until PRG-ON led
turns on. After PRG indication, it appears
NCH indication (number of channels)
If NOP appears please see
“Programming block” paragraph
2 Load number of desired channels Refer to channel leds
(from 1 to 8)
3 PRG/SET It appears ALARM threshold for CH 1
4 Load desired threshold
5 PRG/SET It appears TRIP threshold for CH 1
Follow the same procedure for the number of channels chosen at step 2
6 PRG/SET Fan led blinks
7 Set: YES or NO NO: disabled fan
YES: enabled fan
8 PRG/SET Display shows ON FAN turning on
9 PRG/SET It appears ON threshold for FAN
10 Load desired threshold
11 PRG/SET Display shows OFF FAN turning off
13 Load desired threshold
14 PRG/SET Display shows HFN Fan cyclic test for 5 minutes
each “n” hours
15 Load desired number of hours 000= disabled function
22 PRG/SET Display shows END Programming end
23 ENT Loaded data storage and programming exit Err(2): wrong programming for
values indicated by leds
24 PRG/SET Return to step 1
16 PRG/SET Display shows n.o./ n.c.
and Alarm led blinks Alarm relay working logic
19 Set n.o. or n.c. n.o.: normally open
n.c.: normally closed
17 Set n.o. or n.c. n.o.: normally open
n.c.: normally closed
18 PRG/SET Display shows n.o./n.c.
and Trip led blinks Trip relay working logic
20 PRG/SET Display shows FCD <> “threshold” Fault for fast temperature
increase (°C/sec)
21 Load desired threshold
(see page 10) From “no” up to 30 °C/sec (no: disabled function)
12 PRG/SET It appears OFF threshold for FAN

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NT538 P8 V4-R1.4 protection relays
TECSYSTEM S.r.l ®
20) PROGRAMMING RE-ENABLING IN CASE OF BLOCK (Prg no)
If pressing PRG to enter programming (step 1) “NOP” indication appears, it means that
programming access jumper inside the unit has been removed and therefore this func-
tion is blocked. To reset programming access, mount the jumper as shown in the figure
below.
21) WARRANTY
“NT” series monitoring units are covered by a 12-month warranty starting from the deliv-
ery date on the device itself.
This Guarantee is valid if device should be damaged by causes which can be attributed
to TECSYSTEM S.r.l., such are manufacturing defects of improper calibration.
The warranty is not valid if the monitoring unit would be tampered or if it would be dam-
aged by supply voltages beyond the highest working limits (20÷270 Vac-dc). The war-
ranty is not valid if the device would be burnt out by too many transient voltage peaks.
In this case TECSYSTEM S.r.l. do not answer for damages caused by faulty or defec-
tive monitoring units. All the deliveries (go and back) as well as the repair and servicing
costs for the device will be at Customer’s expenses, reckoned according to ANIMA, Col.
C rates.
In case of contest may only be instituted the Milan court.
The warranty is always FREE OUR DOMICILE in CORSICO.
22) EXTENSION CABLE FOR Pt100 TECHNICAL SPECIFICATIONS
Cable 20xAWG 20/19 Cu/Sn
Section 0,55 mm²
Insulation PVC105 flame-retardant
Standards CEI 20.35 IEC 332.1
Max. working temperature : 105°C
Structure: 4 terns composed of three twisted and coloured wires
Shield in Cu/Sn
Sheath in flame-retardant PVC
External Diameter 9,0 mm
Standard packaging in skein of 100 m
Enabled program-
ming
Disabled pro-
gramming

10 NT538 P8 V4-R1.4 protection relays
TECSYSTEM S.r.l ®
FAULT DIAGNOSTIC CAUSES AND REMEDIES
Monitoring unit doesn’t turn on, even if there is
power supply and the terminals are fed.
Connector not well placed inside its seat. Connec-
tion cables are not tightened in the terminal. Burnt
out feeder.
Take out and give supply again.
One of 8 channels is in FAULT for FOC/FCC
1) Check Pt100 sensor connections: possible de-
fective sensor.
Replace the damaged sensor.
2) Number of channels programmation different to
number of sensors connected.
Repeat programmation.
When turning on, indication “ECH” appears.
A strong disturbance damaged the stored data.
Please refer to paragraph 8.
If this problem should persist, please contact TEC-
SYSTEM S.r.l Technical Department.
All the sensors are in FCC. Wrong sensor connections. Terminal box connected
inside out.
Check connections and terminal box.
Temperature indicated by one or more channel is
wrong. Contact TECSYSTEM S.r.l. Technical Department.
Sudden trip of main switch. Temperature is on
standard levels. Just a channel caused the trip.
Verify through T.MAX function possible defective
sensors.
Replace the sensor. Check the measuring signal
terminal boxes.
23) NOTES ON FCD FUNCTION
NT device series have an innovatory control function combined with the Pt100 probes dynamic
state.
If a thermometric probe should by chance break down, the defect is highlighted with a fast in-
crease of its own resistance and therefore of the temperature recorded by the monitoring device.
It’s obvious that this increase is not directly resulting from the power increase of the machine to
be protected, whether it is a motor or a dry or encapsulated transformer.
Therefore it is necessary to know the state of the probe and send a Fault signal instead of an
Alarm signal or, worse still, a Trip signal.
In case of temperature control on electrical motors, the fast rise in temperature could be caused
by the working with a stalled rotor and not by a defective probe; in this case Fault relay, once
energised, makes clear this anomalous condition for motor working.
Activating FCD function it is possible to have, on contacts 7-8-9, a Fault signal when temperature
recorded by a Pt100 rises with a speed higher than “n” °C/sec (loadable from 1 to 30).
According to the loaded value, you can have a different sensitivity which can be useful for differ-
ent applications:
- from 1 to 10: high sensitivity, for instance useful to immediately detect stalled of a motor rotor.
- From 10 to 20: average sensitivity, useful to get information relevant to possible noises which
affect probe reading, connection problems or defective probes.
- From 20 to 30: low sensitivity, useful for applications where a higher sensitivity could cause a
fault for unwanted FCD’s.
- With “no” FCD function is disabled.
When a channel is in Fault for FCD, relevant Alarm and Trip signalling are inhibited in order to
report just the anomaly for the too fast rise in temperature.
Press Reset to cancel FCD signalling for all the channels and to reset relays fault.

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NT538 P8 V4-R1.4 protection relays
TECSYSTEM S.r.l ®
NT538 ELECTRICAL CONNECTIONS
13 14 15 16 17 18 19 20 21 22 23 24
CH 1 CH 2 CH 3 CH 4
1 2 3 4 5 6 7 8 9 10 11
Pt100 INPUTS
ALARM RELAY OUTPUTS
40
41
42 POWER SUPPLY
24-240 VAC-VDC WHITE
RED
RED
Pt100
FIG.1
ALARM TRIP FAULT FAN
25 26 27 28 29 30 31 32 33 34 35 36
CH 5 CH 6 CH 7 CH 8
ESPANSION MODULE OUTPUT
62
61
60
63
GND RX
RX
GND TX
TX 62
63
GND RX
RX
NT538 EXPANSION
MODULE
61
60 GND TX
TX
If TX is fore-
seen on the
module

12 NT538 P8 V4-R1.4 protection relays
TECSYSTEM S.r.l ®
TEST DECLARATION FOR NT538
Date: ……………
N° Description
1 Mounting card check
2 Input working check
3 Relay contacts and output check
4 Push-button working check
5 Check lamp
6 Calibration at 0 and 200°C
7 Software working check
8 Burn-in min. 24h
This device has passed a test at the origin, according to the following procedure: