GHM Delta OHM HD3405.2 User manual

Our instruments' quality level is the results of the product continuous development. This
can bring about differences between the information written in this manual and the instru-
ment that you have purchased. We cannot entirely exclude errors in the manual, for which
we apologize.
The data, figures and descriptions contained in this manual cannot be legally asserted. We
reserve the right to make changes and correction without prior notice.
REV. 1.0
31 Jan. 2006
HD3405.2

- -
2
Temperature-pH meter
HD3405.2

- -
3
HD3405.2
1. Connectors.
2. Battery symbol: displays the battery charge level. The symbol does not appear when the ex-
ternal power supply is connected.
3. CAL key: it starts the probe the pH electrode calibration.
4. REL key: enables the relative measurement (displays the difference between the current
value and the logged value when the key is pressed). It is applied to the in mV and tempera-
ture measurement.
5. 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.
6. pH/mV key: when pressed for at least one second, changes the main variable measurement
between pH and mV. When the Auto-HOLD function is enabled, slight pressure updates the
measurement.
7. SERIAL/ERASE LOG key: starts and ends data transfer to the serial/USB communication
port. In the menu, clears the data contained in the instrument's memory.
8. °C/°F key: when the probe is not connected, allows manual modification of the temperature.
When double pressed, changes the unit of measurement for the temperature from degrees
Celsius to Fahrenheit.
9. Function indicators.
10. Key : in the menu, increases the current value.
11. Line for symbols and comments.
12. Main display line.
13. ON-OFF/AUTO-OFF key: turns the instrument on and off; when pressed together with the
ENTER key, disables the automatic turn off.
14. MENU key: allows access to and exit from the menu.
15. ENTER in the menu, confirms the current selection; when pressed together with the
ON/OFF key, disables the automatic turn off.
16. ESC key: In the menu, cancels the operation in progress without making changes.
17. FUNC key: during normal operation displays the maximum (MAX), the minimum (MIN)
and the average (AVG) of current measurements.
18. pH electrode efficiency indicators.
19. Key : in the menu, decreases the current value.
20. Secondary display line.
21. External mains power supply connector input 12Vdc for ∅5.5mm - 2.1mm connector.
22. Socket for ∅4 mm standard plug for the reference electrode pH/ISE.
23. BNC connector for the pH/mV electrode.
24. 8-pole DIN45326 connector, input for Pt100 temperature probes with SICRAM module, 4
wire direct Pt100 probes, 2 wire Pt1000 probes.
25. 8-pole MiniDin connector for RS232C connection using cable HD2110CSNM, for USB 2.0
connection using cable HD2101/USB and for S-print-BT printer connection using cable
HD2110CSP.

- -
4
INTRODUCTION
The instrument series HD34… is made up of 4 bench top instruments for electrochemical measures:
pH, conductivity, dissolved oxygen, and temperature.
The HD3405.2 measures pH and the redox potential (ORP) in mV. It measures the temperature
using Pt100 or Pt1000 immersion, penetration or air contact probes.
The pH electrode calibration, as well as manual, can be carried out on one, two or three points and
the calibration sequence can be chosen from a list of 13 buffers.
The displayed data can be stored (datalogger) and can be transferred to PC or serial printer thanks
to the multi-standard serial ports RS232C and USB2.0 and software DeltaLog9 (Vers.2.0 and sub-
sequent ones). The storing and printing parameters can be set from menu.
Display, printing and logging always show temperatures in °C °F, and pH or mV.
Other common function of this instrument series include: Max, Min and Avg function, the Auto-
HOLD function, the automatic turning off which can also be disabled.
The instruments have IP66 protection degree.

- -
5
KEYBOARD AND MENU DESCRIPTION
Foreword
The instrument keyboard is composed of single-function keys, like the MENU key, and double-
function keys such as the LOG/DUMP LOG 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, 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 key
The instrument is turned on and off using the ON/OFF key. Turning on enables all display segments
for a few seconds, starts an auto-test, including the detection of the temperature probe connected to
the input, and sets the instrument ready for normal measurement.
MIN
cm
min s
2
3
m
µ
m
k
>>>
During turning on, should no probes be connected, the message "NO_PRBE_
SER_NUM" is displayed in the line for symbols for a few seconds, and in the secondary
line the last manually-set temperature appears. The unit of measurement symbol (°C or
°F) starts blinking, and a letter "m" meaning "manual" appears next to the battery sym-
bol.
When the probe fitted with SICRAM module is inserted into a functioning instrument,
the "NEW_PROB_DET" (New probe detected) 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 dis-
abled by holding the CAL/key pressed down when turning the instrument on: the battery symbol

- -
6
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.
ENTER key
In the menu, the ENTER key confirms the current parameter and then goes to the next one. Pressed
together with the ON/OFF, disables the automatic turn off.
MENU key
The first menu item is accessed by initially pressing on the MENU key, press ENTER to go the
following. To modify the item displayed , use the arrows key (and ). The current value is
confirmed by pressing the ENTER key and the display moves on to next parameter. If pressing
ESC the setting is cancelled.
To exit the menu, press the MENU key at any time.
The menu items are listed in this order:
1) Management of memorized data: the message "LOG_DUMP_or_ERAS" (Transfer data
or erase) is scrolled in the comment line. The center figure reports the number of free mem-
ory pages (FREE). All memory data are permanently erased by pressing SE-
RIAL/EraseLOG. 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 29).
2) Identifier of the sample being measured: it is an automatically increased progressive
number associated with the single PRINT function (print interval set to 0). The index ap-
pears in the single sample printing together with date, time, pH or mV and temperature
measured values. This menu item allows the value of the first sample to be set: each time the
PRINT key is pressed, the identification ID in the printing is increased by 1 allowing pro-
gressive measurement of all measured samples. If the Auto-Hold function, described below
in this chapter, is enabled, the print time interval is forced to zero. Pressing SERIAL only
causes the print to occur when the measurement has stabilized (HOLD symbol still). Later, it
is possible to repeat the print at will, but while the HOLD mode is on, the sample identifier
number is not increased. This is useful when more labels must be printed with the same
identification code without increasing the code each time.
The message "SMPL ID UNT=RSET SER=PRNT" is scrolled in the comment line: using
the arrows (and ) the currently measured sample identifier value can be changed. By
holding the REL/ key down the proposed number is rapidly set to zero.
The instrument's heading information will be printed using the SERIAL key.
3) AUTO-HOLD function: the instrument normally operates in continuous view mode (de-
fault setting). In this mode the displayed measurement is updated every second. If the Auto-

- -
7
Hold function is enabled, the instrument performs the measurement and when it stabilizes it
goes in HOLD mode. To update the display indication, press “pH/mV” (please see the de-
scription of the pH/mV key for further explanation).
In the following figure you can see an example of the measurement process with the Auto-
Hold function enabled. A electrode is immersed into a liquid and, to perform the measure-
ment, the “pH/mV key is pressed”: The pH measurement raises progressively reaching the
final value. The HOLD symbol blinks. In the sketch indicated by 1, the measurement re-
mains stable for 10 seconds, within two digits: at the end of this interval (point 2), the in-
strument goes into HOLD mode, presenting the final stable value.
2 digit
10s
t
p
H
pH
1
Press the “pH/mV” key again to carry out a new measurement.
4) Print and log interval sets the interval in seconds between two loggings or data transfers to
the serial port. The interval can be set from 0s, 1s, 5s, 10s, 15s, 30s, 60s (1min), 120s
(2min), 300s (5min), 600s (10min), 900s (15min), 1200s (20min), 1800s (30min) e 3600s (1
hour). If the value 0 is set, SERIAL works on command: the sending of data to the se-
rial port is performed each time the key is pressed. Recording (LOG) is performed with
one second intervals even if the interval is set to 0. With an interval from 1 to 3600s, con-
tinuous 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.
5) Sleep_Mode_LOG this function controls the instrument's automatic turning off during log-
ging, 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 auto-
matic turning off, select NO and confirm to disable it and keep the instrument on continu-
ously.
Note: even if Sleep_Mode_LOG=YES is selected, the instrument does not turn off for less
than one minute intervals.
6) LAST CAL m/d h/m (Last pH calibration): the display shows the month and day (m/d) in
the main line, and the hour and minutes (h/m) in the secondary line of the last pH electrode
calibration. This menu item cannot be modified. The calibration year is not displayed.
7) pH RES: selects the number of leading digits for the pH measurement: using the arrows se-
lect 1.23 to obtain the pH hundredths or 1.234 to obtain the thousandths. The chosen resolu-
tion is applied to the new logged measurements, while the previous choice still applies for
the already memorized ones

- -
8
8) BUFR_1 (First buffer): selects the value of the first buffer for the pH electrode calibration.
The preset buffers are compensated for temperature. The ATC indication is displayed in the
lower line. The USER buffer, defined by the user, is not compensated for temperature: to
change its value, go to the "SET USER BUFR" step.
Please see the paragraph dedicated calibration on page.14.
9) BUFR_2 (Second buffer): selects the value of the second buffer for the pH electrode cali-
bration. No standard solution values close (less than 2pH) to the first buffer are proposed.
This is also true for the USER buffer, defined by the user at the "SET USER BUFR" step: if,
for example BUFR_1=6.860 and USER=5.000, the BUFR_2 USER does not appear among
the values because it is too close to BUFR_1. The selection NIL (=no buffer) disables the
current buffer. The USER buffer, defined by the user, is not compensated for temperature.
Please see the paragraph dedicated calibration on page14.
10) BUFR_3 (Third buffer): selects the value of the third buffer for the pH electrode calibra-
tion. No standard solution values close (less than 2pH) to the first buffer are proposed. This
is also true for the USER buffer, defined by the user at the "SET USER BUFR" step: The se-
lection NIL (=no buffer) disables the current buffer. The USER buffer is not compensated
for temperature.
Please see the paragraph dedicated calibration on page 14.
11) SET USER BUFR (Set user pH buffer): this is a buffer whose value can be defined by the
user using the arrows; all values from 0 to 14pH are available. This buffer is not compen-
sated for temperature, so the buffer value must be set at the actual solution temperature. As
an alternative, the correct value according to temperature can be set in the calibration phase.
12) RCD MODE (Record mode): the instrument captures a pH/mV and a temperature value
every second. If the RCD MODE parameter is set to "pH" (factory default), the maximum
and minimum values displayed using FUNC/ENTER refer to pH: the indicated temperature
is that measured at the maximum and minimum pH and is not the maximum and minimum
temperature.
If the RCD MODE parameter is set to "tp" (=temperature), the maximum and minimum
values displayed using FUNC/ENTER refer to temperature: the indicated pH is that meas-
ured at the maximum and minimum temperature and is not the maximum and minimum pH.
Finally, if the RCD MODE parameter is set to "Indep" (=independent), the maximum and
minimum values displayed using FUNC/ENTER are independent: the indicated pH and
temperature are the maximum and minimum measured values but are not necessarily re-
ferred to the same measurement moment.
13) Probe type: the message "PRBE_TYPE" is scrolled in the comment line. The main line in
the center of the display shows the type of temperature probe connected to the instrument.
following probes can be connected to the input:
•temperature probes Pt100 complete with SICRAM module
•4 wire Pt100 probes through module TP47
•2 wire Pt100 probes through module TP47
•2 wire Ni1000 probes through module TP47
Upon turning on the instrument automatically detects the probes fitted with SICRAM mod-
ule, the Delta Ohm Pt1000 and Ni1000: the Probe Type menu item is configured by the in-
strument and cannot be modified by the user.
The temperature probes direct 4 wire Pt100, the Pt1000 and the Ni1000 are manufactured by
Delta OHM. When turned on they display the message "NO_PRBE_SER_NUM". In this

- -
9
case the probe type must be entered manually. Select Probe type using the MENU key and
then select the type of probe used with the arrow keys; confirm using ENTER
14) YEAR: to set the current year. Use the arrows to modify this parameter and confirm using
ENTER.
15) MNTH (month): to set the current month. Use the arrows to modify this parameter and con-
firm using ENTER.
16) DAY: to set the current day. Use the arrows to modify this parameter and confirm using
ENTER.
17) HOUR : to set the current hour. Use the arrows to modify this parameter and confirm using
ENTER.
18) MIN (minutes): to set the current minutes. In order to correctly synchronize the minute, it is
possible to reset the seconds by pressing the °C/°F key. Use the arrows to set the current
minute plus one, and as soon as that minute is reached press °C/°F: this synchronizes the
time to the second. Press ENTER to go onto the next item.
19) 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 us-
ing 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.29).
FUNC key
It enables the display and logging of the maximum (MAX), minimum (MIN) and average (AVG)
value of the pH, mV, and temperature measurements, updating them with the acquisition of new
samples. The acquisition frequency is once a second.
The MAX, MIN and AVG measurements remain in the memory until the instrument is on, even
after exiting the calculation function. To reset the previous values and restart with a new meas-
urement session, press FUNC until the message "FUNC CLR" appears, then use the arrows to
select YES and confirm using ENTER.
The pH and temperature value are displayed at the same time. According to settings in the
"RCD Mode" menu item, the maximum, minimum and average indications have different
meanings: please see the description of this MENU key.
Attention: the data captured using the Record function cannot be transferred to PC.
ESC key
In the menu, the key clears or cancels the active function (ESC).
CAL key
It starts the pH electrode calibration ((please see the paragraph dedicated to calibration page.14).

- -
10
REL key
In measurement mode, displays for both measurements - mV and temperature - the difference be-
tween the current value and that measured on pressing the key. The REL message appears on the
display; press the key again to return to the current measurement.
LOG/DumpLOG key
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 single session.
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.
To end the logging, press LOG.
If the Auto-HOLD function is enabled (please see the menu), the data logging is disabled.
The HD3405.2 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)
When the LOG key is pressed after the MENU key, the transfer of the logged data on the serial port
is started.
Please see the paragraph dedicated to data transfer on page 29.
pH/mV-key
Changes the main variable measurement between pH and mV. The selected parameter is used for
display, printing, and logging.
The instrument has an Auto-Hold function, which can be set in the MENU, that “freezes” the meas-
urement automatically when it has been stable (within 1 mV) for over 10 seconds: the message
HOLD is displayed.
To perform a new measurement, it is necessary to press the pH/mV key.
The HOLD message starts blinking, while the display follows the actual measurement trend, until it
stabilizes again and the HOLD message remains still.

- -
11
NOTE: when the Auto-Hold function is enabled, the pH/mV key allows the pH measurement to be
relaunched, and the measurement in mV is disabled. To restore the display in mV, disable the
Auto-Hold function in the menu.
SERIAL/EraseLOG key
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 printing operation is accompanied by the display of the RS232 symbol and the blinking of the
battery symbol; 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
When pressed after the MENU key, the SERIAL key permanently erases all the data contained in
the instrument's memory.
°C/°F Key
When the temperature probe is connected, the measured value is used to compensate the pH meas-
urement; the key changes the unit of measurement for the temperature from degrees Celsius to
Fahrenheit.
If the probe is not present, the compensation temperature must be entered manually: to manually
change the value shown in the display lower line, press °C/°F once. The temperature indicated
starts blinking. While the display is blinking, it is possible to change the compensation temperature
using the arrows (and ). Confirm using ENTER. The display stops blinking, and that tempera-
ture is used for compensation.
If the temperature probe is not present, to change the unit of measurement between °C and °F, it is
necessary to press twice the °C/°F key.

- -
12
Up Arrow
When used in the menu, it increases the current variable value. During measurement, if the tempera-
ture probe is not present, it increases the temperature value for pH compensation.
Down Arrow
When used in the menu, it decreases the current variable value. During measurement, if the tem-
perature probe is not present, it decreases the temperature value for pH compensation.

- -
13
PHMEASUREMENT
The instrument works with pH measurement electrodes, redox potential measurement electrodes
(ORP), and specific ion electrodes. The probes with 4 wire Pt100, 2 wire Pt1000 or Ni1000 sensors
may be used for measuring temperature or for the automatic compensation of the Nernst coefficient
with the pH electrode.
Some probes are fitted with SICRAM module that acts as an interface between the sensor on the
probe and the instrument. There is a electronic circuit with a permanent memory inside the module
that enables the datalogger to recognize the type of probe connected and to read its calibration in-
formation.
The Delta Ohm Pt1000 and Ni1000 probes complete with TP47 module , are automatically detected
while the direct 4 wire Pt100 temperature probe is not automatically detected by the instrument and
must be set up in the Probe type menu item (please see the description of the menu on page 8).
The pH or mV indication is displayed in the main line; the secondary line shows the temperature.
The electrode for pH measurement
The electrode for pH measurement, generally in glass, generates an electrical signal proportional to
the pH according to Nernst law. The following aspects of this signal are considered:
Zero point: The pH where the electrode generates a potential of 0 mV. In most electrodes, this value
is found at about 7pH.
Offset or Asymmetry Potential: mV generated by an electrode when immersed in a buffer solution at
7pH. Generally oscillates between ± 20 mV.
Slope: response of the electrode expressed in mV per pH units. The theoretical electrode slope at
25°C is 59.16 mV/pH. When the electrode is new the slope is close to the theoretical value.
Sensitivity: it is the electrode's slope expression in relative terms. It is obtained by dividing the ac-
tual value of the slope by the theoretical value, and is expressed as a %. The asymmetry potential
and the slope vary in time with the use of the electrode, which necessitates regular calibration.
The pH electrodes must be calibrated using the standard solutions (see the pH calibration chapter
below). The ORP and specific ion electrodes do not need calibration as their absolute voltage is
measured. The redox standard solutions are only used to check the quality of a redox elec-
trode.
No calibration of the temperature sensor is required by the user: the sensor is calibrated in
the factory and the Callendar Van Dusen parameters are recorded in the SICRAM module.
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.
Automatic or manual pH compensation
In a correct measurement of pH, the results need to be expressed together with the temperature
value at which the reading is performed.
The electrode slope varies according to the temperature in a known mode according to Nernst law:
e.g., a 1pH variation, that at 25°C means 59.16mV, at 100°C means 74.04mV.

- -
14
6pH 7pH
pH
8pH
74.04mV
-74.04mV
59.16mV
-59.16mV
54.20mV
-54.20mV
0mV
mV
T=100°C, 74.04mV/pH
T=25°C, 59.16mV/pH
T=0°C, 54.20mV/pH
When a temperature probe is present, the instrument automatically applies the ATC automatic tem-
perature compensation function. To disable it, the temperature probe must be disconnected.
If the temperature probe is not present, and the correct value is not entered manually, the extent of
the error committed in pH measurement is proportional to temperature and pH value itself.
In absence of the temperature probe, the lower display shows the manually set compensation tem-
perature (default=25°C).
To point this condition out, the °C or °F symbol blinks intermittently near the temperature value.
Moreover, on the main display an "m" (manual) is turned on near the battery symbol (if present).
On the print-outs, the MT indication is printed. Instead, if the probe is present, the AT symbol is
printed.
To manually change the compensation temperature press °C/°F once: the indicated temperature
value starts blinking. Select the desired temperature value by using the arrows and confirm with
ENTER. The display stops blinking, and the temperature displayed is used for compensation.
To change the unit of measurement between °C and °F, it is necessary to press twice the °C/°F key.
pH electrode calibration
The electrode calibration is used to compensate the zero potential and slope deviations to which the
electrode is subject with time.
The calibration frequency depends on the accuracy desired by the user and by the effects that the
measured sample have on the electrode. Generally, we recommend daily calibration, but it is the
user's responsibility from personal experience, to establish the most appropriate frequency.

- -
15
The calibration may be carried out using 1, 2 or 3 points. When using 1 point, the electrode offset is
corrected, with 2 points the offset and the gain is corrected; finally, in case a three points calibration
is carried out two offsets and two slopes are calculated, the second point is the one in which the
zero is performed.
The instrument has a memory of 13 buffers with relevant temperature compensation tables (ATC)
plus an "User" buffer, not compensated. The three buffers can be selected by using the
BUFR_1_pH, BUFR_2_pH, BUFR_3_pH menu items. Usually one for the acid, one for the neu-
tral, and one for the alkaline band will be selected:
@25°C
BUFR_1 (NEUTRAL) 6.860 6.865 7.000 7.413 7.648
BUFR_2 (ACID) 1.679 2.000 4.000 4.008 4.010
BUFR_3 (ALKALINE) 9.180 9.210 10.010
The buffers in bold are predefined in the factory, these are the "Delta OHM" ones.
If electrode calibration was not carried out on the instrument, or the batteries have been changed
or the last calibration failed, the display blinks the CAL message.
Calibration procedure
1) Insert the temperature probe and the electrode in the solution of a calibration buffer. If no tem-
perature probe is available, use another thermometer and enter the value manually as indicated in
the paragraph "Automatic or manual pH compensation”.
2) The electrode calibration mode is started by pressing CAL.
3) Among the three prepared buffers, the instrument automatically detects the closest to the pH
value being read and flags it up on the lower display.
If the buffer is not detected the first buffer BUFR_1_pH is proposed.
4) At this point the CAL symbol is not blinking on the display and the following is shown from the
upper side downward:
a) the chosen buffer nominal value at 25°C (scrolling indication)
b) the pH measurement value with the current calibration
c) the temperature compensated buffer value
The detected and temperature compensated buffer value, shown in the lower line, can be modi-
fied using the arrows.
5) To proceed with the calibration press ENTER. The electrode offset mV value (OFFS) is shown
on the display for few seconds).
After a few seconds the instrument shows the measurement again, corrected according to the
new calibration, but remains in calibration mode. Pressed repeatedly the ENTER key allows
the calibration on the point to be repeated, for example, in order to obtain a more stable value.
6) To end the electrode calibration, press "ESC" to exit calibration, or continue the calibration for
the second point.

- -
16
7) Extract the electrode from the buffer, clean it carefully, and insert it in the following buffer.
8) Press the MENU key .
The instrument displays the value detected on the new buffer: continue by repeating the steps from
point 3).
NOTES:
•After calibration, the instrument displays an electrode quality indication:
•No signal: electrode functioning.
•1 small square blinking on the lower right: electrode almost exhausted.
•2 small squares blinking on the lower right: electrode exhausted to be replaced.
•The 3 point calibration must always be carried out according to the fixed sequence: NEU-
TRAL>>ACID>>BASIC. The basic buffer must be the last in the sequence.
•Without having pressed ENTER at all, the calibration is interrupted by pressing ESC; the
previous values will continue to be used.
•The buffers are always presented in the sequence set in the menu with the BUFR_1-BUFR_2-
BUFR_3 parameters. The 2 point calibration is possible using the sequence BUFR_1-BUFR_2
or BUFR_2-BUFR_3 or even BUFR_1-BUFR_3. The 3 point calibration is only possible us-
ing the exactly described sequence BUFR_1-BUFR_2-BUFR_3.
Allowed pH calibration sequences
1 BUFR_1 BUFR_2 BUFR_3
2 BUFR_1 - BUFR_2 BUFR_2 - BUFR_3 BUFR_1 - BUFR_3
Number of
calibration
points
3 BUFR_1 - BUFR_2 - BUFR_3
•A buffer can be disabled in the option selection phase (MENU mode) by choosing the NIL
value. In this case, the disabled buffer is excluded from the sequence and will not be proposed.
•In any case where no operation is performed, the calibration mode automatically stops af-
ter 60 seconds.
•If the calibration is rejected by the instrument because it is considered to be excessively cor-
rupted, the CAL ERR message will appear, followed by a long beep. The instrument remains in
calibration mode and maintains the previous calibration values: at this point, if the calibration is
interrupted using ESC, the instrument signals the anomaly through the CAL message blinking.

- -
17
Temperature characteristics of Delta OHM buffer solutions
The 13 standard buffers reported in the table on page 14 are memorized in the instruments with
relevant variations according to temperature: The characteristics of the three Delta Ohm standard
buffers at 6.86pH, 4.01pH and 9.18pH (@25°C) are reported below, 4.01pH e 9.18pH (@25°C)
6.86 pH @ 25°C 4.01 pH @ 25°C
°C pH °C pH °C pH °C pH
0 6.98 50 6.83 0 4.01 50 4.06
5 6.95 55 6.83 5 4.00 55 4.07
10 6.92 60 6.84 10 4.00 60 4.09
15 6.90 65 6.85 15 4.00 65 4.10
20 6.88 70 6.85 20 4.00 70 4.13
25 6.86 75 6.86 25 4.01 75 4.14
30 6.85 80 6.86 30 4.01 80 4.16
35 6.84 85 6.87 35 4.02 85 4.18
40 6.84 90 6.88 40 4.03 90 4.20
45 6.83 95 6.89 45 4.05 95 4.23
9.18 pH @ 25°C
°C pH °C pH
0 9.46 50 9.01
5 9.39 55 8.99
10 9.33 60 8.97
15 9.28 65 8.94
20 9.22 70 8.92
25 9.18 75 8.90
30 9.14 80 8.88
35 9.10 85 8.86
40 9.07 90 8.85
45 9.04 95 8.83

- -
18
DIRECT INPUT INTO Pt100, Pt1000 AND Ni1000 TEMPERATURE PROBES WITH TP47 MODULE
The instrument accepts the input of Platinum temperature probes with resistances of 100Ωand
1000Ωas well as Nickel temperature probes with a 1000Ωresistance.
The Pt100 are connected to 4 wires, the Pt1000 and Ni1000 to 2 wires, with the excitation current
chosen minimizing the sensor self-heating effects.
All probes with module are calibrated in the factory, the 2 or 4 wire probes with direct input are
checked for conformity with class A tolerance according to norm IEC751 - BS1904 - DIN43760.
The probes with SICRAM module, Pt1000 and Ni1000 TP47 module are detected by the instru-
ment; the model configuration is required for the other probes (please see the description of the
Probe Type menu on page 8).
The °C or °F unit of measurement can be chosen for display, printing, and logging using the °C/°F –
ESC key.
How to measure
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 module for 4 wire Pt100 probes, Pt1000 and Ni1000
All Delta Ohm probes are provided with a module TP47. The HD3405.2 also work with direct 4
wire Pt100 probes, Pt1000 and Ni1000 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 or Nickel probe to the TP47 module are provided below.
The module is supplied complete with fairlead and gasket for 5mm maximum diameter cables.

- -
19
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:
Open the two module shells: the printed circuit to which the temperature 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 card. These must be closed with a tin bead for some type
of sensors:
1
2
3
4
Pt100 3 fili
Pt1000
Ni1000
Not Used
Before welding, pass the probe cable through the fairlead and gasket. Weld the temperature sensor
wires as shown in the table:
Sensor TP47 card connection Jumper
Pt100 4 wires
4JP4
3JP3
1JP1
2JP2
Pt100
4 wires
None
Pt1000 2 wires
JP4
4
JP3
3
JP1
1
JP22
Pt1000
2 wires
JP2
Ni1000
JP4
4
JP3
3
JP1
1
JP2
2
Ni1000
2 wires
JP3

- -
20
Ensure the welds are clean and perfect. Once the welding operation is complete, close the two
shells, insert the gasket in the module, screw the fairlead. 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 the 4-sensor to a DIN45326 connector
Sensor 4 wire Pt100 can be welded
directly to the DIN45326 female
connector’s pins without having to
resort to the TP47 board. The 4 wires
of Pt100 must be soldered as shown
in the diagram to the left.
To use this type of probe, set the
“Probe Type” item in the menu as
stated in page 8.
Probe Pt100 is acknowledged by the
device upon start-up: insert the probe
when the device is on and only start
up after insertion.
Sensor Direct connection to the connector
Pt100 4 wires
Female Connector on the welding