HT instruments HT950N User Manual

HT950N

Panel meter for temperature control

User’s manual

Copyright HT-ITALIA 2003 Release EN 1.04 - 13/10/04

HT950N

Index:

1. SAFETY PRECAUTIONS AND PROCEDURES ...................................................................... 3

1.1. Preliminary ............................................................................................................ 3

1.2. During use ............................................................................................................. 3

2. GENERAL DESCRIPTION ....................................................................................................... 4

3. PREPARATION TO USE .......................................................................................................... 4

3.1. Initial ...................................................................................................................... 4

3.2. Power supply ......................................................................................................... 4

3.3. Calibration ............................................................................................................. 4

3.4. Storage .................................................................................................................. 4

4. OPERATING INSTRUCTIONS ................................................................................................. 5

4.1. Description front panel ........................................................................................... 5

4.2. Description of function keys ................................................................................... 6

4.3. Description of back panel ...................................................................................... 7

5. OPERATIVE INSTRUCTIONS .................................................................................................. 8

5.1. Installation ............................................................................................................. 8

5.2. Electrical connections ............................................................................................ 8

5.2.1. Power supply circuit .......................................................................................... 9

5.2.2. Temperature probes ....................................................................................... 10

5.2.3. CONTR output circuit ...................................................................................... 10

5.2.4. T1 output alarm circuit .................................................................................... 11

5.2.5. T2 output alarm circuit .................................................................................... 11

5.3. Messages on Power-ON ..................................................................................... 11

5.4. Setup of alarm thresholds .................................................................................... 12

5.4.1. Example of HT950N meter setup .................................................................... 13

5.5. Clear of recorded max temperature value ........................................................... 13

5.6. Setup of input probes number ............................................................................. 14

6. PREVENTIVE MAINTENANCE .............................................................................................. 14

6.1. General information ............................................................................................. 14

6.2. Cleaning .............................................................................................................. 14

7. TECHNICAL SPECIFICATIONS ............................................................................................. 15

7.1. Technical Characteristics .................................................................................... 15

7.1.1. Inputs characteristics ...................................................................................... 15

7.1.2. Output characteristics ..................................................................................... 15

7.1.3. Safety characteristics ...................................................................................... 15

7.1.4. General characteristics ................................................................................... 15

7.2. Environmental conditions .................................................................................... 15

7.2.1. Climatic conditions .......................................................................................... 15

7.2.2. EMC ................................................................................................................ 15

7.3. Accessories ......................................................................................................... 15

7.3.1. Standard accessories ..................................................................................... 15

8. SERVICE ................................................................................................................................ 16

8.1. Warranty conditions ............................................................................................. 16

8.2. Service ................................................................................................................ 16

EN - 1

HT950N

1. SAFETY PRECAUTIONS AND PROCEDURES

This meter is designed in conformity to EN61010 standards relating to electronic
measuring instruments. For your own safety and that of the apparatus, you must follow the
procedures described in this instruction manual and specially read all the notes preceded

by the symbol carefully.
Strictly keep to the following instructions before and during measurements:

 Do not install the meter in environments with explosive gas, fuels or dust.
 Do not install in case of unusual conditions of the instrument such as deformation,

breakage, leakage of substances, absence of display reading etc.

The following symbols are used in this manual:

WARNING

No compliance with the Warnings and/or Instructions may damage the
apparatus and/or its components or injure the operator.

1.1. PRELIMINARY

 Use the meter only as specified in this manual; otherwise, the protection provided by

the meter may be impaired.

 Only the accessories supplied with the instrument guarantee compliance with the

safety standards. They must be in good conditions and must be replaced, if necessary,
with identical models.

 Do not effect measurements beyond the limits specified in this manual.
 Take care that indications on display its according with selected function.

1.2. DURING USE

Carefully read the following recommendations and instructions:

WARNING

No compliance with the Warnings and/or Instructions may damage the
apparatus and/or its components or injure the operator.
Safety protection for the meter maybe damaged.

 Use the meter and the temperature probes only within the ranges specified in the

chapter 7.1.1 of manual.

 Do not perform any measurement on materials under voltage. This could damage the

instrument.

EN - 3

HT950N

2. GENERAL DESCRIPTION

Dear Customer, we thank you for your patronage. The HT950N meter you have just
purchased will grant you accurate and reliable measurements, on protection of MV
transformer, provided that it is used according to the present manual’s instructions.

The HT950N model it was been designed with high quality electrical components and,
during test verify, it’s subject to BURN-IN test to eliminate any internal bugs due to rapid
death rate of components.

The HT950N meter presents the following features:
 1 up to 4 input temperature signals, selectable by key, from same number of thermo

sensitivity elements Pt100 DIN type with three wires.

 Measurement range from 0° to 200°C.
 Automatic compensation of 3-wire cable resistance.
 Setting of two alarm thresholds temperature T2 and T1, with T2>T1, programmable on

all measurement range, with activation of the same number of output relays.

 Setting of two alarm thresholds temperature UA and UF, with UF<UA with activation of

an output relay. These thresholds can be used to activate a possible forced ventilation
system or a parallel device.

3. PREPARATION TO USE

3.1. INITIAL

The instrument has been checked from every point of view before shipment. Every care
has been taken to make sure that the instrument reaches you in perfect conditions.
However, it’s advisable to make a rapid check in order to detect eventual damages, which
may have occurred in transit. Should this be the case, enter immediately the usual claims
with the carrier. Make sure that all the accessories listed in paragraph 7.3.1are contained
in the package. In case of discrepancies contact the dealer.

In case of returning of the tester, please keep to the instructions given in chapter 8.

3.2. POWER SUPPLY

The instrument can be supplied with a voltage between 24 and 240 V AC (50/60 Hz) or DC
voltage.

3.3. CALIBRATION

The instrument complies with the technical features listed in this manual.

3.4. STORAGE

In order to guarantee the accuracy of the measurements, after a period of storage in
extreme environmental condition, wait for the necessary time so that the instrument
returns to normal measuring conditions (see paragraph 7.2.1).

EN - 4

HT950N

4. OPERATING INSTRUCTIONS

4.1. DESCRIPTION FRONT PANEL

LEGEND:

1. Principal Display

2. PARAmeters Display

3. SET Display

4. Function keys

HT950N

Controller

Fig. 1: Instrument description, frontal view

 CONTROL Led
The light on of this Led mean that temperature of one of four inputs is over the setting UA
threshold value and the CONTR output relay is closed. This can active the start of forced
ventilation system or a parallel device. The Led light off only when temperature decrease
under UF threshold value and the CONTR relay is open. This can disconnect the forced
ventilation system or a parallel device (see Fig. 9 ).

 PT100 Led
This Led shows that at least one of four controlled input probes (2U, 2V, 2W or 1F Led is
blinking) is shorted or opened. In this case an alarm condition is activated by HT950N and
relay T1 is opened.

 2U-2V-2W-1F Led
These Leds shows, for each of four columns:

 With fixed light means the temperature column you can read on principal display.
 With blinking light, together Pt100 light on, means problems at the correspondent

thermoresistance.

 T1 Led
This Led have the following functions:
 When is light on its shows that temperature of one of four probes is over T1 threshold

set on HT950N and correspondent relay have activated pre-alarm condition (see Fig.

9).

 When is light off, with Pt100 Led fixed light on, its shows one of following conditions:

1. Disconnection of one of four input Pt100 (with correspondent blinking led).

2. One Pt100 is shorted (like point 1.).

3. No one power supply at meter.

EN - 5

HT950N

 T2 Led
This Led shows that measured temperature by one of four probes is over T2 alarm
threshold set on HT950N and correspondent relay is activated. This means transformer
turn off (see Fig. 9).

 T.MAX Led
This Led is light on when you press T.MAX key and show the maximum temperature
recording by HT950N during all measured period. SET display shows the temperature
value and PARA display shows the column (C1=2U, C2=2V, C3=2W, C4=1F) of
correspondent maximum value.

 ERROR Led
This Led is light on if there is an error on setting threshold temperature values. In particular
for T2<T1 or UA<UF wrong set conditions.

 Principal Display
This display always show the real time temperature of the hot column.

 SET Display
This display shows the following temperatures:

 T2 temperature of transformer turn off during threshold setting.
 T1 temperature of pre-alarm during threshold setting.
 UA temperature of forced ventilation activation during threshold setting.
 UF temperature of forced ventilation disable during threshold setting.
 Maximum temperature recording by HT950N during measurements.
 Temperature of four columns C1, C2, C3, C4.

 PARA Display
This display show the control parameter (T2, T1, UF, UA) and the columns symbol (C1,
C2, C3, C4).

4.2. DESCRIPTION OF FUNCTION KEYS

 PARA key
This key can activate the setting of thresholds temperature. Refer to chapter 5.4 for any
details.

 ALT.T. key
Press this key the HT950N meter shows real temperatures on the four columns. PARA
display shows the columns names C1=2U, C2=2V, C3=2W, C4=1F and SET display
shows the correspondent temperature values. These displays light off in the following
three ways: press ENT. Key, press ALT.T. key when C4 column appair or automatically
after about 20 sec. From last operation.

 TEST key
Press this key HT950N execute a functionally test on verify the light on of all Led and
displays on the front panel.

EN - 6