Delta OHM HD2124.1 User manual



Operating manual
Manometers / thermometers
HD2124.1 – HD2124.2
www.deltaohm.com
Companies / Brands of GHM
English
Keep for future reference.

HD2124 - 2 - V2.5
CONTENTS
INTRODUCTION..................................................................................................................................................... 3
INPUTS CONFIGURATION AND DISPLAY ........................................................................................................ 8
KEYBOARD AND MENU DESCRIPTION ............................................................................................................ 9
THE PROBES..........................................................................................................................................................15
PP471 MODULE FOR PRESSURE MEASUREMENT ........................................................................................................15
Pt100 TEMPERATURE PROBE ...................................................................................................................................16
How to measure ................................................................................................................................................16
Instructions to connect the TP47 connector for 4-wire Pt100..............................................................................16
Direct connection of 4-wire Pt100 sensors .........................................................................................................17
WARNINGS AND OPERATING INSTRUCTIONS ..............................................................................................18
INSTRUMENT SIGNALS AND FAULTS..............................................................................................................19
LOW BATTERY WARNING AND BATTERY REPLACEMENT.......................................................................21
INSTRUMENT STORAGE.....................................................................................................................................22
SERIAL INTERFACE AND USB ...........................................................................................................................23
STORING AND TRANSFERRING DATA TO A PERSONAL COMPUTER......................................................25
THE LOGGING FUNCTION -ONLY FOR HD2124.2......................................................................................................25
CLEARING THE MEMORY -ONLY FOR HD2124.2 ......................................................................................................25
THE PRINT FUNCTION ...........................................................................................................................................26
CONNECTION TO A PC........................................................................................................................................27
CONNECTION TO THE RS232C SERIAL PORT OF THE INSTRUMENT .............................................................................27
CONNECTION TO THE USB 2.0 PORT OF THE INSTRUMENT -ONLY FOR HD2124.2......................................................27
NOTES ABOUT WORKING AND OPERATIVE SAFETY..................................................................................28
INSTRUMENT TECHNICAL CHARACTERISTICS...........................................................................................29
TECHNICAL DATA OF PROBES AND MODULES IN LINE WITH THE INSTRUMENT ............................................................31
Measurement of pressure by module PP471.......................................................................................................31
Temperature probes Pt100 using SICRAM module............................................................................................32
Probes Pt100 4 wires.........................................................................................................................................32
ORDER CODES ......................................................................................................................................................33

HD2124 - 3 - V2.5
INTRODUCTION
The HD2124.1 and HD2124.2 are portable instruments with a large LCD display. They perform
measurements of absolute, relative and differential pressure, and temperature.
The PP471 electronic module is used to measure the pressure. The PP471 electronic module works
as an interface between the instrument and the TP704 and TP705 series Delta Ohm probes.
The temperature is detected with immersion, penetration, contact or air Pt100 probe with SICRAM
module or 4-wire Pt100 probe.
The temperature probes are fitted with SICRAM module and the factory calibration settings are
already memorized inside. Upon turning on the instrument automatically detects them.
The HD2124.2 instrument is a datalogger. It memorizes up to 32,000 samples that can be
transferred from the instrument connected to a PC via the RS232C serial port or USB 2.0 port. The
memorization interval, printing, and baud rate can be configured using the menu.
The HD2124.1 and HD2124.2 models are fitted with an RS232C serial port and can transfer the
acquired measurements in real time to a PC or to a portable printer.
The Max, Min and Avg function calculate the maximum, minimum or average values, the Peak
function detects the presence of pressure peaks, the A-B function calculates the difference of the
pressures or temperatures measured by the two inputs A and B.
Other functions include: the relative measurement REL, the HOLD function, and the automatic
turning off that can also be disabled.
The instruments have IP66 protection degree.
This manual describes the HD2124.1 and HD2124.2 models: if not otherwise specified, the
description is intended to be applicable to both models.

HD2124 - 4 - V2.5
Manometer - Thermometer
HD2124.1

HD2124 - 5 - V2.5
HD2124.1
1. Input A, 8-pole DIN45326 connector. It is possible to connect: the PP471 extension cable for
TP704 and TP705 pressure probes or a Pt100 temperature probe fitted with SICRAM module
or 4-wire Pt100 probe.
2. Input B, 8-pole DIN45326 connector. It is possible to connect: the PP471 extension cable for
TP704 and TP705 pressure probes or a Pt100 temperature probe fitted with SICRAM module
or 4-wire Pt100 probe.
3. External auxiliary power supply connector input.
4. Battery symbol: displays the battery charge level.
5. Functions indicators
6. Secondary display line.
7. HOLD/key: freezes the measurement during normal operation; in the menu, increases the
current value.
8. FUNC/ENTER key: during normal operation displays the maximum (MAX), the minimum
(MIN) and the average (AVG) of current measurements; in the menu, confirms the current
selection.
9. REL/key: enables the relative measurement (displays the difference between the current
value and the logged value when the key is pressed); in the menu, decreases the current value.
10. SERIAL key: starts and ends the data transfer to the serial communication port.
11. PEAK key: starts and ends the peak measurement.
12. MENU key: allows access to and exit from the menu.
13. A/B-ESC key: with two pressure probes connected to the A and B inputs, this displays the A
channel, the B channel and the A-B pressure difference in sequence. The measurement appears
on the main line. With two temperature probes, this displays the B channel or the A-B pressure
difference in the secondary line. In the menu cancels the operation in progress without making
changes.
14. UNIT key: selects the unit of measurement for the pressure.
15. ON-OFF/AUTO-OFF key: turns the instrument on and off; when pressed together with the
HOLD key, disables the automatic turn off.
16. MAX, MIN, AVG and Peak symbols: peak indicates that displayed value is the peak of the
current measurement; MAX, MIN and AVG that the displayed temperature or pressure values
are respectively the minimum, maximum or average value.
17. Main display line.
18. Multiplication factor -3, 3 or 6: the apex, if present, indicates that the displayed measurement
must be divided by 1000 (apex "-3"), multiplied by 1000 (apex "3") or by 1,000,000 (apex "6").
19. Line for symbols and comments.
20. 8-pole MiniDin connector for RS232C. For the connection to PC (with cable HD2110CSNM or
C206) or printer (with cable HD2110CSNM).

HD2124 - 6 - V2.5
Manometer - Thermometer
HD2124.2

HD2124 - 7 - V2.5
HD2124.2
1. Input A, 8-pole DIN45326 connector. It is possible to connect: the PP471 extension cable for
TP704 and TP705 pressure probes or a Pt100 temperature probe fitted with SICRAM module
or 4-wire Pt100 probe.
2. Input B, 8-pole DIN45326 connector. It is possible to connect: the PP471 extension cable for
TP704 and TP705 pressure probes or a Pt100 temperature probe fitted with SICRAM module
or 4-wire Pt100 probe.
3. External auxiliary power supply connector input.
4. Battery symbol: displays the battery charge level.
5. Functions indicators.
6. Secondary display line.
7. HOLD/key: freezes the measurement during normal operation; in the menu, increases the
current value.
8. FUNC/ENTER key: during normal operation displays the maximum (MAX), the minimum
(MIN) and the average (AVG) of current measurements; in the menu, confirms the current
selection.
9. REL/key: enables the relative measurement (displays the difference between the current
value and the logged value when the key is pressed); in the menu, decreases the current value.
10. SERIAL/ERASE LOG key: starts and ends the data transfer to the serial communication port.
In the menu, clears the data contained in the instrument's memory.
11. LOG/DUMP LOG key: during normal operation, starts and ends the saving of the data in the
internal memory; in the menu, starts the data transfer from the instrument's memory to the PC.
12. Mini-USB type B connector for USB 2.0. For the connection to PC (with cable CP23).
13. PEAK/MENU key: during normal operation, starts and ends the peak measurement. When
pressed together with the FUNC/ENTER key, allows access to the menu. To exit the menu,
press the key again.
14. A/B-ESC key: with two pressure probes connected to the A and B inputs, this displays the A
channel, the B channel and the A-B pressure difference in sequence. The measurement appears
on the main line. With two temperature probes, this displays the B channel or the A-B pressure
difference in the secondary line. In the menu cancels the operation in progress without making
changes.
15. UNIT key: selects the unit of measurement for the pressure.
16. ON-OFF/AUTO-OFF key: turns the instrument on and off; when pressed together with the
HOLD key, disables the automatic turn off.
17. MAX, MIN, AVG and Peak symbols: peak indicates that displayed value is the peak of the
current measurement; MAX, MIN and AVG that the displayed temperature or pressure values
are respectively the minimum, maximum or average value.
18. Main display line.
19. Multiplication factor -3, 3 or 6: the apex, if present, indicates that the displayed measurement
must be divided by 1000 (apex "-3"), multiplied by 1000 (apex "3") or by 1,000,000 (apex "6").
20. Line for symbols and comments.
21. 8-pole MiniDin connector for RS232C. For the connection to PC (with cable HD2110CSNM or
C206) or printer (with cable HD2110CSNM).

HD2124 - 8 - V2.5
INPUTS CONFIGURATION AND DISPLAY
The HD2124.1 and HD2124.2 are instruments with two pressure and temperature inputs. To
measure pressure, the PP471 SICRAM module is used with one of the Delta Ohm TP704 or TP705
probes. The temperature is measured using Pt100 probes fitted with SICRAM module or 4-wire
Pt100 probes.
The instruments handle the following configurations: two pressure probes, two temperature probes,
or a temperature and a pressure probe.
The two inputs for the probes are identified by letters A and B: as reported on the instrument label,
the B channel is on the left and the A channel is the central one.
Inputs configuration:
1) Two PP471 pressure modules connected to the A and B inputs.
The two pressure measurements are both displayed in the main line. Pressing the A/B-ESC key
in sequence displays the A channel, the B channel and, if the two probes are equal, the A-B
pressure difference. The channel is displayed in the secondary line: A (Ch A) or B (Ch B). When
the difference is shown, the A-B symbol is turned on.
The maximum (MAX), the minimum (MIN) and the average (AVG) are always indicated in the
main line alternating with the current measurement: for detailed information see the
FUNC/ENTER key description in the next chapter.
2) PP471 module connected to the central channel A, Pt100 probe connected to the channel B.
The pressure is displayed in the main line; the secondary line shows the temperature.
3) Pt100 probe connected to the central channel A, PP471 module connected to the channel B.
The pressure is displayed in the main line; the secondary line shows the temperature.
4) Two Pt100 temperature probes connected to the A and B inputs.
The measurement provided by the probe connected to the A channel is displayed in the main
line. The secondary line shows the measurement provided by the probe connected to the B
channel. Pressing the A/B-ESC key in sequence displays the A channel in the secondary line, the
temperature measured by channel B channel and the difference A-B between the two
temperatures. When the difference is shown, the A-B symbol is turned on. The unit of
measurement (°C or °F) is the same for both temperatures.

HD2124 - 9 - V2.5
KEYBOARD AND MENU DESCRIPTION
Foreword
The instrument keyboard is composed of single-function keys, like the UNIT key, and double-
function keys such as the ON-OFF/Auto-OFF key.
In the double-keys, the function in the upper part is the “main function”, while the one in the bottom
part is the “secondary function”. When the instrument is in standard measurement mode, the main
function is active. In the menu or in conjunction with the FUNC key, the secondary function is
enabled.
The pressing of a key is accompanied by a short confirmation beep: a longer beep sounds if the
wrong key is pressed.
Each key specific function is described in detail below.
ON-OFF/Auto-OFF key
The instrument is turned on and off using the ON/OFF key. The turning on enables all display
segments for a few seconds, starts an auto-test including the detection of the probes connected to
the inputs, and sets the instrument ready for normal measurement. During the auto-test, the serial
number of the connected probes is indicated in the comment line: e.g. "CH_A_SER_1234_5678"
means the probe with serial number 12345678 is connected to the central input A.
MIN
cm
min s
2
3
m
µ
m
k
>>>
If no probe is connected to input A, the "CH_A_NO_ SER_NUM" message appears for a few
seconds in the line for symbols. Similarly, the "CH_B_NO_ SER_NUM" message is scrolled
for input B.
When a probe equipped with SICRAM module is inserted into a functioning instrument, the
"NEW_CH_A_PROB_DET" or "NEW_CH_B_PROB_DET" ("New probe detected in
channel A" or "New probe detected in channel B") message appears: as the probe's data are
captured upon turning the instrument on, it is necessary to turn the instrument off and on
again.
Replace the probes when the instrument is off.
+
Automatic turning off
The instrument has an AutoPowerOff function that automatically turns the instrument off after about
8 minutes if no key is pressed during the intervening time. The AutoPowerOff function can be

HD2124 - 10 - V2.5
disabled by holding the HOLD key pressed down when turning the instrument on: the battery
symbol will blink to remind the user that the instrument can only be turned off by pressing the
<ON/OFF> key.
The automatic turning off function is disabled when external power is used. On the other
hand, it cannot be disabled when the batteries are discharged.
FUNC/ENTER key
During normal measurement this enables the display of the maximum (MAX), minimum (MIN) and
average (AVG) value of the measurements captured by the probe connected to the instrument,
updating them with the acquisition of new samples. The acquisition frequency is once a second.
The MAX, MIN and AVG calculation begins upon turning on and is updated when the instrument
is in normal measurement mode. To reset the previous values and restart with a new measurement
session, press FUNC until the message “FUNC CLR” appears, then use the arrows to select YES
and confirm using ENTER.
The MAX, MIN and AVG pressure is always displayed in the main line: in cases where two
probes are connected to the inputs, use A/B-ESC to move from one variable to the other.
The MAX, MIN and AVG temperature is always displayed with the respective instantaneous
temperature: main line for channel A and secondary line for channel B.
In the menu, the ENTER key confirms the current parameter and then goes to the next one. Pressed
together with the PEAK/MENU key, opens the menu (please see the PEAK/MENU key
description).
Attention: the data captured using the Record function cannot be transferred to the PC.
HOLD/key
It increases the current parameter when used in the menu; when used in measurement mode, it
freezes the measurement in progress, and upon application of pressure on the key, the message
HOLD appears in the upper side of the display. To return to the current measurement, press the
key again.
Upon turning on the instrument, the AutoPowerOff function can be disabled by holding the HOLD
key down (please see the ON-OFF key description).
UNIT key
In measurement mode, it allows selection of the unit of measurement of the pressure (shown in the
central line of the display). By repeatedly pressing the key, the different units of measurement are
displayed in sequence: Pa, hPa, kPa, mbar, bar, atm, mmHg, mmH2O, kgf/cm2, PSI, inchHg, inchH2O.
This setting changes the information displayed and the immediate print of data (SERIAL key).

HD2124 - 11 - V2.5
The data recorded using the LOG function (HD2124.2) keep the chosen unit of measurement
displayed during logging.
The unit of measurement associated with the data sent to the printer or PC through the serial
port by using the SERIAL function, must be selected before starting the print function.
A/B-ESC key
If two pressure probes are connected to the inputs, the main line displays the A channel, then the B
channel, and finally, if the probes are equal, the A-B pressure difference.
With two temperature probes, the lower line displays, alternately, the B channel instantaneous
measurement and indication of the A-B difference. The main line continues to display channel A
temperature.
When used in the menu, it clears or cancels the active function.
REL/key
In measurement mode, it displays the difference between the current value and that measured on
pressing the key for both measurements - main and secondary. The REL message appears on the
display; press the key again to return to the current measurement.
When used in the menu, it decreases the current variable value.
MENU key - only HD2124.1
+
PEAK/MENU key - only HD2124.2
The first menu item is accessed by initially pressing on the MENU key (FUNC/ENTER +
PEAK/MENU in the HD2124.2 model); press ENTER to go to the following items. To modify the
item displayed, use the arrow keys (and ). The current value is confirmed by pressing the
ENTER key and the display moves on to the next parameter. By pressing the ESC key, the setting is
cancelled.
To exit the menu, press the MENU or the PEAK/MENU key at any time.
The menu items are listed in this order:
1) Probes zeroing: the zero command operates simultaneously on the inputs A and B.
•In the differential pressure probes leave the two inputs open, so that they detect the
same pressure.
•In the relative pressure (compared to the atmosphere) probes, leave the input open,
so that it detects the atmospheric pressure.

HD2124 - 12 - V2.5
•In the absolute pressure probes, apply the vacuum by using a suitable pressure
calibrator.
The "PRES_REL_TO_ZERO ENTR_TO_MENU" message appears: press REL to zero the
pressure or press ENTER to access other menu items. Press A/B – ESC to toggle from one
channel to the other: the zero is still applied to both A and B channels.
2) Management of stored data (only HD2124.2): the message “>>>_LOG_DUMP_or_E-
RAS” (Transfer data or erase) is scrolled in the comment line. The center figure reports
the number of free memory pages (FREE). Pressing SERIAL/EraseLOG permanently erases
all memory data. By pressing LOG/DumpLOG, the data transfer of the logged data on the
serial port is started: the “BAUD-RATE” must have previously been set to the maximum
value (please see the menu items described below and the paragraph "STORING AND
TRANSFERRING DATA TO A PERSONAL COMPUTER" on page 25).
3) Print and log interval: sets the interval in seconds between two loggings or data transfers
to the serial port. The interval can be set at 0, 1s, 5s, 10s, 15s, 30s, 60s (1min), 120s (2min),
300s (5min), 600s (10min), 900s (15min), 1200s (20min), 1800s (30min) and 3600s (1hour).
If the value 0 is set, SERIAL works on command: the sending of data to the serial port
is performed each time the key is pressed. Recording (LOG) is performed with 1 second
intervals even if the interval is set to 0. With an interval from 1 to 3600s, continuous data
transfer is started when the SERIAL key is pressed. To end the recording (LOG) and
continuous data transfer operations (SERIAL with an interval greater than 0), press the
same key again.
4) Sleep_Mode_LOG (Automatic turning off during recording) (only HD2124.2): this
function controls the instrument's automatic turning off during logging, occurring between
the capture of a sample and the next one. When the interval is lower than 60 seconds, the
instrument will always remain on. With intervals greater than or equal to 60 seconds, it is
possible to turn off the instrument between loggings: it will turn on at the moment of
sampling and will turn off immediately afterwards, thus increasing the battery life. Using the
arrows select YES and confirm using ENTER in order to enable the automatic turning off,
select NO and confirm to disable it and keep the instrument on continuously.
Note: even if Sleep_Mode_LOG=YES is selected, the instrument does not turn off for less
than one minute intervals.
5) °C/°F selection:sets the unit of measurement for the temperature. the message SEL_MEAS
UNIT" is scrolled in the comment line: using the arrows select °C or °F and confirm with
ENTER.
6) CH A (channel A probe type): the characteristics of the probe connected to input A are
shown. For the pressure, the full scale and the type of sensor connected to the PP471
SICRAM module are reported. For the temperature, the indication ”Pt100Sicr” or ”Pt100
4W ” is reported.
7) CH B (channel B probe type): the characteristics of the probe connected to input B are
shown. For the pressure, the full scale and the type of sensor connected to the PP471
SICRAM module are reported. For the temperature, the indication ”Pt100Sicr” or ”Pt100
4W ” is reported.
8) YEAR: to set the current year. Use the arrows to modify this parameter and confirm using
ENTER.
9) MNTH (month): to set the current month. Use the arrows to modify this parameter and
confirm using ENTER.

HD2124 - 13 - V2.5
10) DAY: to set the current day. Use the arrows to modify this parameter and confirm using
ENTER.
11) HOUR: to set the current hour. Use the arrows to modify this parameter and confirm using
ENTER.
12) MIN (minutes): to set the current minutes. In order to synchronise the minute correctly, it is
possible to reset the seconds by pressing the UNIT key. Use the arrows to set the current
minute plus one and as soon as that minute is reached press UNIT: this synchronizes the
time to the second. Press ENTER to go onto the next item.
13) BAUD_RATE: indicates the frequency used for the serial communication with the PC.
Values from 1200 to 38400 baud. Use the arrows to modify this parameter and confirm
using ENTER. The communication between instrument and PC (or serial port printer)
only works if the instrument and PC baud rates are the same. If the USB connection is
used this parameter value is automatically set (please see the details on page 25).
PEAK key - only HD2124.1
PEAK/MENU key - only HD2124.2
The PEAK (HD2124.1) or PEAK/MENU (HD2124.2) keys enable the pressure peak measurement
circuit. When two probes are present, use the A/B key to move from one channel to the other.
The Peak indication blinks and the current pressure is shown. When a peak is detected (a positive
variation greater than 5% compared to current measurement), the Peak indication remains on for 5
seconds and its value is displayed. If, in the meantime, a higher peak than the previous one is
detected, the indication is updated. From 5 seconds after the previously detected peak, the Peak
indication returns to blinking and the current pressure is shown.
To keep the maximum peak on the display, select the peak function and then the record MAX
function using FUNC/ENTER. This way, the display continuously shows the maximum peak
reached during measurement. Before starting new measurements, clear the memory of previous
measurements using "FUNC CLR": please see the FUNC/ENTER key description.
The Logging function during peak measurement (only HD2124.2):
To record the maximum peaks, start the peak function and then the record function (LOG key). As
the measured peak is maintained for about 5 seconds, in order to avoid losing any peak, use 1
second logging intervals. Indeed, using longer times the single event could occur between two
subsequent recording and be ignored.
LOG/DumpLOG key - only HD2124.2
In measurement mode, this function starts and stops the logging of a data block to be saved in the
instrument's internal memory. The data logging frequency is set in the "Print and log interval"
menu parameter. The data logged between a start and subsequent stop represent a block.
When the logging function is on, the LOG indication is displayed, the battery symbol blinks and a
beep is issued each time a logging occurs; the battery symbol does not appear when using an
external power supply.

HD2124 - 14 - V2.5
To end the logging, press LOG.
The HD2124.2 can turn off during logging between one capture and the next: the function is
controlled by the Sleep_Mode_LOG parameter. When the logging interval is less than one minute,
the logging instrument remains on; with an interval of at least one minute, it turns off between one
capture and the next if the parameter Sleep_Mode_LOG=YES.
[
+
]>>> Dump LOG - only HD2124.2
To start the transfer of the data contained in the instrument internal memory via the serial port, press
simultaneously the FUNC/ENTER and PEAK/MENU keys, using ENTER select the
“>>>_LOG_DUMP_or_ERAS” item, and then press on the LOG/DumpLOG key.
Please see the paragraph dedicated to data transfer on page 25.
SERIAL key - only HD2124.1
SERIAL/EraseLOG key - only HD2124.2
In measurement mode, this function starts and stops the data transfer to the RS232C serial output.
According to the settings entered in the Print and log interval menu item, a single sample can be
printed if Print and log interval=0 or a continuous indefinite printing of the measured data can be
set up if Print and log interval=1…3600.
The display of the RS232 symbol and the blinking of the battery symbol accompany the printing
operation; when using an external power supply the battery symbol does not appear.
Press SERIAL to end the continuous printing.
Before starting the printing with SERIAL, set the baud rate. To do so, select the Baud Rate menu
item and select the maximum value equal to 38400 baud by using the arrows. Confirm by pressing
ENTER.
The DeltaLog9 software for PC will automatically set the baud rate value during connection. If you
are using a different program than DeltaLog9, be sure the baud rate is the same for both the
instrument and the PC: the communication will only work in this way.
[
+
]>>> Erase memory - only HD2124.2
Press simultaneously the FUNC/ENTER and PEAK/MENU keys, using ENTER select the
“>>>_LOG_DUMP_or_ERAS” item, and then press on the SERIAL/EraseLOG key: this clears
permanently all the data contained in the instrument’s memory.

HD2124 - 15 - V2.5
THE PROBES
The instrument measures absolute, relative and differential pressure using the PP471 SICRAM
module and the TP704 and TP705 series probes. It also measures the temperature with a Pt100
sensor fitted with SICRAM module or 4-wire Pt100 probes.
The SICRAM module acts as an interface between the sensor on the probe and the instrument.
There is a microprocessor circuit with a permanent memory inside the module that enables the
datalogger to recognize the type of probe connected and to read its calibration information.
The probes are detected during turn on, and this cannot be performed when the instrument is
already on, therefore if a probe is connected and the instrument is on, it is necessary to turn it
off and on.
The manometers are fitted with two inputs dedicated to the probes: it is possible to connect one or
two pressure probes, one or two temperature probes or one pressure probe and one temperature
probe. See the details on page 8.
The probes are fitted with SICRAM modules are calibrated in the factory; no calibration is required
by the user.
PP471 MODULE FOR PRESSURE MEASUREMENT
The PP471 module acts as an interface between the TP704 and TP705 series Delta Ohm probes and
the instrument. The TP704 series pressure probes have a 1/4” BSP threaded male connection and
must be screwed in the joint where you wish to measure the pressure. The TP 705 series have two
Ø5 connections where the suitable tubes are inserted in order to perform the desired measurement.
Please pay careful attention to the joint pressure sealing; use suitable gaskets and joints. A plastic
cap protects the threaded connection. Put it back after use as it protects the pressure cell from
foreign bodies. VERY IMPORTANT: ensure the probe's full scale is higher that the pressure
that will be measured. In case this value is unknown, start by using higher-capacity probes.
For every pressure probe a range of overload pressure and a burst pressure are declared:
pressures in the range of overload pressure don’t cause the break of the sensor but the
declared accuracy can be overcome. Pressure over the stated burst pressure may break the
sensor. The application of higher pressures than the overload pressure limit, although lower
than the burst pressure, may produce permanent damage to the probe (e.g. offset shift). Never
exceed the stated burst pressure.
Please see the technical characteristics of the probes on page 31.
Upon turning on the instrument automatically detects the PP471 module. The probe's type
(absolute, relative or differential) and full scale value are detected even when the instrument is on.
If no logging or recording operations are in progress, it is possible to change the probe connected to
the module without turning the instrument off and on again.
The measurement provided can be the instantaneous or the peak value of the pressure: please see
the PEAK key description on page 13.
To change the instantaneous or peak value unit of measurement, press UNIT. The following units of
measurement are available:
Pa, hPa, kPa, mbar, bar, atm, mmHg, mmH2O, kgf/cm2, PSI, inchHg, inchH2O.
Some following units of measurement require a multiplication factor: the “-3” symbol indicates the
displayed value must be divided by 1,000; the "3" and "6" symbols indicate the displayed value
must be multiplied respectively by 1,000 or by 1,000,000.

HD2124 - 16 - V2.5
Pt100 TEMPERATURE PROBE
The instrument accepts the input of Platinum temperature probes with resistances of 100Ω.
The Pt100 sensors are connected to 4 wires; the excitation current was chosen in order to minimize
the sensor self-heating effects.
All probes are calibrated in the factory; no calibration is usually required by the user.
The °C or °F unit of measurement can be chosen for display, printing, and logging using the
“SEL_MEAS UNIT” menu item.
How to measure
The response time for the measurement of the temperature in air is greatly reduced if the air is
moving. If the air is still, stir the probe. Please remember that the response times in any case are
longer than those for liquid measurements.
The temperature measurement by immersion is carried out by inserting the probe in the liquid for at
least 60mm; the sensor is housed in the end part of the probe.
In the temperature measurement by penetration the probe tip must be inserted to a depth of at least
60mm, the sensor is housed in the end part of the probe. When measuring the temperature on frozen
blocks it is convenient to use a mechanical tool to bore a cavity in which to insert the tip probe.
In order to perform a correct contact measurement, the measurement surface must be even and
smooth, and the probe must be perpendicular to the measurement plane.
So as to obtain the correct measurement, the insertion of a drop of oil or heat-conductive
paste is useful (do not use water or solvents). This method also improves the response time.
Instructions to connect the TP47 connector for 4-wire Pt100
All probes produced by Delta Ohm are provided with a connector. The HD2124.1 and HD2124.2
instruments also work with 4-wire direct Pt100 probes manufactured by other producers: for the
instrument connection is prescribed the TP47 connector to which the probe's wires should be
welded.
The instructions to connect the Platinum probe to the module are provided below.
The module is supplied complete with fairlead and gasket for 5mm maximum diameter cables.
Do the following to open the module and connect a probe:
Unscrew the fairlead and extract the gasket, remove the label using a cutter, unscrew the ring on the
opposite side as illustrated in the figure:

HD2124 - 17 - V2.5
Open the two module shells: the printed circuit to which the probe must be connected is housed
inside. On the left there are the 1…4 points on which the sensor wires must be welded. The
JP1…JP4 jumpers are in the center of the board. For the 4-wire Pt100 sensor the jumpers must be
left open.
1
2
3
4
Pt100 3 wires
Pt1000
Ni1000
Not Used
Before welding, pass the probe cable through the fairlead and gasket.
Weld the wires as shown in the table:
Sensor Board connection Jumper to close
Pt100 4 wires
4JP4
3JP3
1JP1
2JP2
Pt100
4 wires
None
Ensure the welds are clean and perfect. Once the welding operation is complete, close the two
shells, insert the gasket in the module, and screw the fairlead and the ring. At the other end of the
module, enter the ring with the O-Ring as indicated in the picture.
Make sure the cable is not twisted while you are screwing the fairlead.
Now the probe is ready.
Direct connection of 4-wire Pt100 sensors
4-wire Pt100 sensor can be soldered
directly to the pins of the free female
connector without making use of the
TP47 board. The 4 wires of the Pt100
sensors have to be soldered as indicated
in the figure on the left.
The P100 probe is recognized upon
turning on the instrument: connect the
probe when the instrument is switched
off and then turn it on. The use of this
probe type doesn’t require any other
settings.
Sensor Direct soldering to the connector
4-wire
Pt100
View of the soldering side
of the free female connector

HD2124 - 18 - V2.5
WARNINGS AND OPERATING INSTRUCTIONS
1. Do not expose the probes to gases or liquids that could corrode the material of the sensor or the
probe itself. Clean the probe carefully after each measurement. Some pressure probe models
are suitable for measurement of non corrosive gases or air and dry and not liquid only: check
the membrane compatibility with the plant fluid.
2. Do not bend the probe connectors or force them upward or downward. Do not bend or force the
contacts when inserting the probe connector into the instrument.
3. Do not bend, deform or drop the probes, as this could cause irreparable damage.
4. Always select the most suitable probe for your application.
5. Do not use probes in presence of corrosive gases or liquids. The sensor container is made of
AISI 316 stainless steel, while the contact probe container is made from AISI 316 stainless
steel plus silver. Avoid contact between the probe surface and any sticky surface or substance
that could corrode or damage it.
6. Above 400°C and below –40°C, avoid violent blows or thermal shocks to Platinum temperature
probes as this could cause irreparable damage.
7. To obtain reliable measurements, temperature variations that are too rapid must be avoided.
8. Temperature probes for surface measurements (contact probes) must be held perpendicular
against the surface. Apply oil or heat-conductive paste between the surface and the probe in
order to improve contact and reduce reading time. Whatever you do, do not use water or
solvent for this purpose. A contact measurement is always very hard to perform. It has high
levels of uncertainty and depends on the ability of the operator.
9. Temperature measurements on non-metal surfaces usually require a great deal of time due to
the low heat conductivity of non-metal materials.
10. Probes are not insulated from their external casing; be very careful not to come into contact
with live parts (above 48V). This could be extremely dangerous for the instrument as
well as for the operator, who could be electrocuted.
11. Avoid taking measurements in presence of high frequency sources, microwave ovens or large
magnetic fields; results may not be very reliable.
12. Clean the probe carefully after use. Clean the probe pressure chamber carefully. Avoid deposits
or incrustations left by the fluid coming into contact with the membrane, as with time this could
cause measurement errors.
13. Avoid inserting nails or spikes into the pressure chamber as the membrane could be
unintentionally torn.
14. In order to fix the probes, use a suitable fixed wrench, and possibly sealing gaskets.
15. Great attention must be paid while installing the probes in containers and tubes under
pressure. Also pay attention to the probes' bottom scale. In addition to the
irreparable damage, it can even cause serious physical damage to both the
operator and things. Before the probe a stop valve should always be present.
Ensure that the plant is not subject to abnormal or unexpected depressed fluid
fluctuations.
16. The instrument is water-resistant and IP66, but is not watertight and therefore should not be
immersed in water without closing the free connectors using caps. The probe connectors must
be fitted with sealing gaskets. Should the instrument fall into the water, check for any water
infiltration. Gently handle the instrument in such a way as to prevent any water infiltration from
the connectors' side.

HD2124 - 19 - V2.5
INSTRUMENT SIGNALS AND FAULTS
The following table lists all error indications and information displayed by the instrument and
supplied to the user in different operating situations.
Display indications Explanation
CH_A COMM LOST
ERR
This appears if the SICRAM module connected to input A, has
already been detected by the instrument, but is disconnected. At the
same time an intermittent beep is issued.
CH_B COMM LOST
ERR
This appears if the SICRAM module connected to input B, has already
been detected by the instrument, but is disconnected. At the same time
an intermittent beep is issued.
CH_A CH_B
COMM LOST
ERR
This appears if the SICRAM modules connected to inputs A and B,
have already been detected by the instrument, but are both
disconnected.
At the same time an intermittent beep is issued.
OVER
Measurement overflow: this appears if the pressure sensor exceeds the
limit of 120% of the bottom scale nominal value. Over 125%, the
display indicates ERR.
Measurement overflow: this appears if the external temperature probe
is measuring a value exceeding the set measuring range.
ERR This appears in the menu, under the “CH A” and “CH B” items, if a
SICRAM module that has already been recognised is disconnected.
LOG
MEM
FULL
Memory full; the instrument cannot store further data, the memory
space is exhausted.
PROB
ERR
A probe with SICRAM module has been inserted when not admissible
for that specific instrument.
SYS
ERR
#
Instrument management program error. Contact the instrument's
supplier and communicate the numeric code # reported by the display.
CAL
LOST
Program error: it appears after turning on for a few seconds. Contact
the instrument's supplier.
BATT TOO LOW
CHNG NOW
Indication of insufficient battery charge appearing on turning on. The
instrument issues a long beep and turns off. Replace the batteries.

HD2124 - 20 - V2.5
The following table reports the indications provided by the instrument as they appear on the display,
together with their description.
Display indications Explanation
### BAR ABS
p
robe ###bar absolute
### BAR DIFF
p
robe ###bar differential
### BAR GAUG
p
robe ###bar relative
### BAR SG
p
robe ###bar relative compared to 1 bar
### mBAR ABS
p
robe ###mbar absolute
### mBAR DIFF
p
robe ###mbar differential
### mBAR GAUG
p
robe ###mbar relative
>>>
_
LOG
_
DUMP
_
or
_
ERAS transfer or erase data
BATT TOO LOW - CHNG NO
W
battery discharged - replace it immediatel
y
BAUDRATE >>
>
baud rate valu
e
CH
_
Achannel A
CH
_
A CH
_
B COMM LOST lost communication with probes connected to inputs A and B
CH
_
A COMM LOST lost communication with probe connected to input A
CH
_
A
_
NO
__
SER
_
NUM the serial number of the probe connected to input A is absent
CH
_
A
_
SER #### ###
#
serial number #### #### of the probe connected to input A
CH
_
Bchannel B
CH
_
B COMM LOST lost communication with probe connected to input B
CH
_
B
_
NO
__
SER
_
NUM the serial number of the probe connected to input B is absent
CH
_
B
_
SER #### ###
#
serial number #### #### of the probe connected to input B
COMM STO
P
p
rinting complete
COMM STRT
p
rinting starte
d
DAY
_
da
y
DUMP
_
END data transfer complete
DUMP
_
In
_
PROG >>
>
data transfer in progress
ERR error
FUNC CLR max, min and average values clearing
FUNC CLRD max, min and average values cleare
d
HOUR hour
LOG In PROG logging in
p
rogress
LOG MEM FULL memory full
LOG
_
CLRD memory data cleare
d
LOG
_
STO
P
logging complet
e
LOG
_
STRT logging starte
d
MIN >>> USE
_
UNIT
_
TO
_
ZERO SEC minutes >>> use the UNIT key to reset the seconds
MNTH month
NEW
_
CH
_
A
_
CH
_
B
_
PROB
_
DET two new probes connected to inputs A and B detecte
d
NEW
_
CH
_
A
_
PROB
_
DET new probe connected to input A detected
NEW
_
CH
_
V
_
PROB
_
DET new probe connected to input B detecte
d
OVER maximum limit exceede
d
PLS
_
EXIT >>> FUNC RES
_
FOR
_
FACT
ONLY please exit using ESC >>> function reserved to factory calibration
PRES
_
REL
_
TO
_
ZERO ENTR
_
TO
_
MEN
U
p
ress REL to reset
p
robe or ENTER to access menu
PRNT AND LOG INTV
p
rinting and logging intervals
PRNT INTV >>
>
p
rinting interval
PROB ERR error - unexpected probe
SEL
_
MEAS UNIT selection of the unit of measurement for temperature (°C or °F)
SLP
_
MODE
_
LOG turning off during recording mode
SYS ERR
#
p
rogram error number
#
YEAR year