Order Codes - Delta OHM HD 2011T serie Handbuch

Aktive transmitter von feuchtigkeit und programmierbare temperatur

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near doors, in the presence of draughts or in areas where there is no movement of

air.

During use, check the compatibility of the sensor with the atmosphere in

which it is installed.

Assembly

The instrument is offered in three different configurations to satisfy every applica-

tion requirement. These are:

TO horizontal version, generally for installation in a channel; a sliding joint is avail-

able for fixing in channels or on walls with a 1/2" gas thread;

TV vertical version for installation on the wall;

TC version with cable. The probe is connected to the electronics by means of a

cable of various lengths and it may operate in a temperature range of

-40...+150°C.

Attention: in TC models the sensor and the electronics have the same serial

number, they cannot be exchanged with other transmitters unless the instru-

ment is recalibrated in line with the new probe.

Programming

The transmitters of the series HD 2011T... and HD 2012T... are equipped with a

calibrated relative humidity probe and temperature probe. The humidity and tem-

perature outputs can each be selected, independently, with a jumper between

0mA...20mA, 4mA...20mA or 0V...10V. When it leaves the factory the transmit-

ter is already set as follows:

Relative humidity

4mA

Temperature

4mA

The user cam recalibrate the humidity probe, as long as he maintains the corre-

spondence 4mA (or 0mA or 0V) = 0%R.H. and 20mA (or 10V) = 100%R.H. while

he can set a different range for the temperature output (-50...+200°C).

A) Calibration of the humidity probe

The following procedure refers to the output set for a current of 4...20mA: for the

other outputs it is sufficient to shift the jumper before starting the calibration opera-

tion.

The following accessories are required:

• a source of alternating power supply at 24Vac or 230Vac depending on the mod-

els (check the data on the plate);

• a precision ammeter with a minimum range 0÷25mA.

Calibration of the humidity probe is carried out on two fixed points: the first point

is always 75.4%R.H. and the second point is always 33%R.H., proceeding as

follows:

• supply power to the instrument as shown in the wiring diagrams in Fig.5

(HD 2011T...) and Fig.6 (HD 2012T...);

• insert the probe in the container with the 75%R.H. saturated solution and wait at

least 30 minutes;

• move the jumper from "MEASURE" position to "CAL 75%" position;

• press the key marked "Program switch R.H." and hold it down for at least 5

seconds until the corresponding led starts to blink. At this point it is possible to

release the key: the led remains lit. A sensor inserted in the probe compensates

the temperature difference of the solution with respect to 20°C;

• insert the probe in the container with the 33%R.H. and wait at least 30

minutes;

• move the jumper to "CAL 33%" position;

• press the key marked "Program switch R.H." and hold it down for at least 5

seconds until the corresponding led goes out. At this point it is possible to re-

lease the key, the ammeter will indicate a current of 9.28mA if the solution is at

20°C. If the solution is at a different temperature, the current indicated by the

ammeter will be equal to the value shown in the following table:

°C

%R.H.

33.4

33.3

32.7

9.34

9.33

9.28

9.23

• return the jumper to "MEASURE" position. This concludes calibration of the R.H.

probe.

Important note: the first calibration point must always be 75%R.H.

B) Programming the temperature output 4-20mA for HD 2012T... models

The following procedure refers to the output set for a current of 4...20mA: for the

other outputs it is sufficient to shift the jumper before starting the calibration opera-

tion.

The following accessories are required:

• a source of alternating power supply at 24Vac or 230Vac depending on the mod-

els (check the data on the plate);

0%R.H.

20mA

100%R.H.

0°C

20mA

100°C

32.4

31.6

31.1

9.18

9.12

9.06

8.98

• Pt100 calibrator or a set of precision resistances;

• a precision ammeter with a minimum range 0...25mA.

Procedure

• Connect the temperature section of the HD 2012T... as shown in Fig.6, set the

Pt100 calibrator at the temperature corresponding to 4mA. For example, sup-

posing you want to set the range -10...+120°C, the calibrator will be set at -10°C:

the equivalent resistance value will be 96.09Ω; if calibration is performed with a

fixed resistance, a fixed resistance with a value of 96.09Ω will be connected be-

tween the terminals 11 and 12, with the terminals 10 and 11 short circuiting.

• Wait 10 seconds until the measurement has stabilised, hold down "Program

switch °C" for at least 5 seconds until the LED blinks once and remains lit.

• Set the Pt100 calibrator at the temperature value contemplated for 20mA. Ac-

cording to the example above, the calibrator will be set at +120°C: the equiva-

lent resistance value will be 146.07Ω; if calibration is performed with a fixed re-

sistance, a fixed resistance with a value of 146.07Ω will be connected between

the terminals 11 and 12, with the terminals 10 and 11 short circuiting.

• Wait 10 seconds until the measurement has stabilised, hold down "Program

switch °C" for at least 5 seconds until the LED goes out. When the key is re-

leased the led blinks twice to confirm that programming has been completed. At

this point the procedure is ended.

• Check that the setting corresponds to the required specifications, setting the cal-

ibrator (or connecting the precision resistances) at the values corresponding to 4

and 20mA and checking the current in the ammeter.