GHM DeltaOHM HD2305.0 User manual

Operating Manual
pH Meter / Thermometer
HD2305.0
www.deltaohm.com
English
Keep for future reference
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HD2305.0 - 2 - V1.6
SOMMARIO
GENERAL CHARACTERISTICS.................................................................................................................................3
DESCRIPTION OF THE FUNCTIONS........................................................................................................................6
THE PROGRAMMING MENU .....................................................................................................................................9
PROBES AND MEASUREMENT................................................................................................................................10
THE ELECTRODE FOR pH MEASUREMENT ........................................................................................................10
Automatic or manual pH compensation 11
How to manually change the temperature 11
pH ELECTRODE CALIBRATION.......................................................................................................................................12
Calibration procedure 12
Temperature characteristics of Delta OHM buffer solutions 14
4WIRE Pt100 AND 2WIRE Pt1000 TEMPERATURE PROBES .........................................................................................15
Temperature measurement 15
Connecting the TP47 module for the 4 wire Pt100 and 2 wire Pt1000 probes 15
Direct connection of 4 wire Pt100 sensors to a DIN45326 connector 17
WARNINGS....................................................................................................................................................................18
INSTRUMENT SIGNALS AND FAULTS ..................................................................................................................19
INSTRUMENT STORAGE...........................................................................................................................................20
Notes on pH electrodes use 20
LOW BATTERY WARNING AND BATTERY REPLACEMENT .........................................................................21
WARNING ABOUT BATTERY USE ...................................................................................................................................21
NOTES ABOUT WORKING AND OPERATIVE SAFETY.....................................................................................22
TECHNICAL CHARACTERISTICS ..........................................................................................................................23
TECHNICAL INFORMATION ON THE pH METER –THERMOMETER ..................................................................................23
INSTRUMENT PROBES AND MODULES TECHNICAL DATA ...........................................................................24
PHELECTRODES.......................................................................................................................................................24
SONDE DI TEMPERATURA..............................................................................................................................................24
TEMPERATURE PROBES PT100 SENSOR USING SICRAM MODULE....................................................................................24
Pt100 4-WIRE AND Pt1000 2-WIRE PROBES COMPLETE WITH TP47 MODULE..................................................................24
ORDERING CODES......................................................................................................................................................25

HD2305.0 - 3 - V1.6
GENERAL CHARACTERISTICS
The pH meter - Thermometer Model HD2305.0 is a portable instrument that allows measurement of
pH and redox potential (ORP) in mV.
It also measures the temperature using Pt100 or Pt1000 immersion, penetration or contact probes.
The electrode calibration can be carried out on one, two or three points at 4.01pH, 6.86pH and
9.18pH.
The temperature probes are fitted with the SICRAM automatic detection module, with the factory
calibration settings already being memorized inside.
The units of measurement for the measurable quantities are:
pH
mV
°C
°F
Using the Max, Min and Avg function of this instrument respectively obtains the maximum, mini-
mum or average values.
Other available functions are:
the relative measurement REL;
the automatic turning off which can also be disabled.

HD2305.0 - 4 - V1.6
pH meter - Thermometer
HD2305.0

HD2305.0 - 5 - V1.6
HD2305.0
1. 8-pole DIN45326 connector, input for Pt100 temperature probes with Sicram module, 4 wire di-
rect Pt100 probes, 2 wire Pt1000 probes complete with TP47 module.
2. pH/mV input, female BNC
3. Battery symbol: displays the battery charge level.
4. Function indicators.
5. Secondary display line.
6. DATA/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 se-
lection. In calibration mode, acquires the nominal buffer value.
7. pH-mV/ESC key: during normal operation switches the display between pH and mV; in the
menu, resets the value set with the arrows. In calibration mode, allows you to exit calibration.
8. key: in the menu, increases the current value. In calibration mode, increases the displayed
nominal buffer value.
9. °C/°F/MENU key: it allows selection of the unit of measurement; when pressed together with
the DATA key, it allows to open the menu.
10. CAL: starts the calibration procedure.
11. /REL-mV key: during normal operation enables the relative measurement (displays the dif-
ference between the current value and the logged value when the key is pressed); press the key
again to return to the normal measurement. It works only if you are displaying the mV.In the
menu, decreases the current value. In calibration mode, decreases the displayed nominal buffer
value.
12. ON-OFF/AUTO-OFF key: turns the instrument on and off; when pressed together with the
°C/°F/MENU key, disables the AutoPowerOff function.
13. MAX (maximum value), MIN (minimum value) and AVG (average value) symbols.
14. Main display line.
15. Line for symbols and comments.

HD2305.0 - 6 - V1.6
DESCRIPTION OF THE FUNCTIONS
The keyboard of the pH meter Model HD2305.0 is composed of double-function keys. The function
on the key is the "main function", while the one above the key is the "secondary function".
When the instrument is in standard measurement mode, the main function is active.
Once the Settings Menu has been opened, by pressing simultaneously the DATA+°C/°F keys, 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.
This key has two functions:
ON/OFF: to turn the instrument on press ON, to turn it off press OFF.
The turning on enables all display segments for a few seconds, starts an Auto-test including the de-
tection of the probe connected to the input, and sets the instrument ready for normal measurement.
The following is displayed:
MIN
cm
min s
2
3
mµ
m
k
>>>
AUTO/OFF: the AutoPowerOff function can be disabled by simultaneously pressing this key
and the "°C/°F-MENU" key when turning the instrument on.
During turning on, should no probes be connected, the "NO_PRBE_SER_NUM" message is dis-
played in the line for symbols for a few seconds, while the "ERR" message is shown in the central
part of the display, and the last manually-set temperature appears in the secondary line. The unit of
measurement symbol (°C or °F) starts blinking, and a letter "m" meaning "manual" appears next to
the battery symbol.
When the probe fitted with SICRAM module is inserted into a functioning instrument, the
"NEW_PROB_DET" (New probe detected) message appears, while the "ERR" message is
shown in the central part of the display, and a sequence of "beeps" is simultaneously issued. As the
data are captured upon turning the instrument on, it is necessary to turn it off and on again.
Caution! Replace the probes when the instrument is off.
ON-OFF and AUTO-OFF key

HD2305.0 - 7 - V1.6
The "pH-mV" key has three functions:
pH-mV: pressing this key once switches the display between pH and mV;
ESC: once the MENU has been opened with the DATA+°C/°F keys, the "pH-mV" key will al-
low to cancel the parameters set using the and arrows.
In calibration mode, it allows to exit calibration.
The "DATA" key is used for the following functions:
DATA: during normal measurement, by pressing this key once the maximum (MAX) value of
the measurements captured by the probe connected to the instrument is displayed, updating it
with the acquisition of new samples;
-by pressing this key again the minimum (MIN) value is displayed;
-by pressing this key, a third time the average(AVG) value is displayed.
The acquisition frequency is once a second.
The MAX, MIN and AVG values remain in the memory until the instrument is on, even after
exiting the DATA display function. When the instrument is off, the previously memorized data
are cleared. Upon turning on, the instrument automatically starts memorizing the MAX, MIN
and AVG values.
To reset the previous values and start with a new measurement session:
press DATA until the FUNC_CLRD message appears;
use the and arrows to select YES;
confirm by pressing ENTER.
ENTER: once the MENU has been opened with the DATA+°C/°F keys, the DATA key will
perform the ENTER function and the MENU can be browsed and the displayed parameter con-
firmed. In calibration mode, acquires the nominal buffer value.
Una volta entrati nel MENU, tramite i tasti DATA e °C/°F, il tasto permetterà di incrementare il
valore del parametro selezionato nel MENU. In calibrazione permette di incrementare il valore del
buffer nominale.
Il tasto °C/°F viene utilizzato per le seguenti funzioni:
°C/°F: when the temperature probe is connected, the key changes the unit of measurement 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
TDATA/ENTER key
Tasto pH-mV/ESC
key
°C/°F/MENU Key

HD2305.0 - 8 - V1.6
change the compensation temperature using the arrows (and ). Confirm using DA-
TA/ENTER. The display stops blinking, and the temperature displayed is used for compensa-
tion. 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.
MENU: to access to the menu press simultaneously DATA+°C/°F: the Probe Type will be
displayed.
use the and arrows (respectively located above the HOLD and REL keys) to modify
the displayed value;
press DATA/ENTER to confirm the modification and go onto the next item;
press CLR/ESC to cancel the modification;
to exit the menu, press the °C/°F key again.
For more info, please see following chapter.
Press this key to start the calibration procedure (vd. par. pH).
The "/ REL-mV" key is used for the following functions:
REL-mV: it displays the difference between the current value and that measured on pressing
the key. The "REL" message is displayed on the left. To return to the normal measurement,
press the key again. It only works with mV, so to enable the REL function select the "mV" unit
of measurement using the "pH-mV" key.
: Once the MENU has been opened with the °C/°F/MENU key, the key will allow to de-
crease the value of the selected parameter. During electrode calibration, it allows to decrease the
nominal buffer value
/ REL-Mv key
CAL key

HD2305.0 - 9 - V1.6
THE PROGRAMMING MENU
To access to the menu press simultaneously the following keys:
The item to be set is:
Probe type: the "PRBE_TYPE_RTD_" message is displayed in the comment line. The main line
in the center of the display shows the type of probe connected to the instrument. The following
probes can be connected to the input:
temperature probes Pt100 complete with SICRAM module
4 wire Pt100 probes through module TP47
2 wire Pt1000 probes through module TP47
The probes fitted with SICRAM module, and Delta Ohm Pt1000 probes, are automatically detected
by the instrument upon turning on: the Probe Type menu item is configured by the instrument and
cannot be modified by the user.
The temperature probes direct 4 wire Pt100, and the Pt1000 probes that are not manufactured by
Delta OHM, when turned on display the message "NO_PRBE_SER_NUM". In this case the probe
type must be entered manually.
Access to the menu by selecting Probe type using the DATA and °C/°F keys at the same time:
-use the and arrows to modify the displayed value;
-press DATA/ENTER to confirm the modification and go onto the next item;
-press pH-mV/ESC to cancel the modification;
-to exit the menu, press the °C/°F key again.

HD2305.0 - 10 - V1.6
PROBES AND MEASUREMENT
The instrument works with the following probes:
electrodes for pH measurement;
electrodes for redox potential ORP measurement (REDOX);
specific ion electrodes.
Caution! The pH measurement is influenced by the temperature measurement.
The temperature is used for the automatic compensation of the Nernst coefficient with the pH
electrode.
The measurement can be performed using probes with the following sensor:
4 wire Pt100;
2 wire Pt1000;
Some probes are fitted with SICRAM module that 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 instrument to recognize the type of probe connected and to read its calibra-
tion information.
The Delta Ohm Pt1000 probes 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 menu description on chapter 3).
The pH or mV indication is displayed in the main line; the secondary line shows the temperature.
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 probes fitted with SICRAM module are calibrated in the factory; no calibration is required by
the user.
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. Of this signal the following aspects are considered:
Zero point: The pH where the electrode generates a potential of 0 mV. In most electrodes, this
value is found at about 7 pH.
Offset or Asymmetry Potential: represents the potential (in mV) generated by an electrode when
immersed in a buffer solution at 7 pH. 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
actual value of the slope by the theoretical value, and is expressed as a %. The asymmetry po-
tential and the slope vary in time with the use of the electrode, which necessitates regular cali-
bration.

HD2305.0 - 11 - V1.6
The pH electrodes must be calibrated using the buffer solutions (see paragraph pH electrode calibra-
tion).
The ORP and specific ion electrodes do not need calibration as their absolute voltage is measured.
The ORP (REDOX) buffer solutions are only used to check the quality of an ORP (REDOX) elec-
trode.
User calibration of the temperature sensor is not required: the sensor is calibrated in the fac-
tory and the Callendar Van Dusen parameters are recorded in the SICRAM module.
Automatic or manual pH compensation
In a correct measurement of pH, the results need to be expressed together with the temperature val-
ue 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.
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 function: au-
tomatic temperature compensation. 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 part of the display shows the manually set compen-
sation temperature. By default, it is equal to 25°C (see par. 4.1.2 how to manually change the tem-
perature).
To point this condition out, the °C or °F symbol blinks intermittently near the temperature value.
Moreover, in the main line an "m" (that is, manual) is turned on near the battery symbol.
How to manually change the temperature
In absence of the temperature probe, it is possible to manually set the temperature. Proceed as fol-
lows:
press the °C/°F key once: the indicated temperature value starts blinking;
select the solution temperature value by using the arrows;
confirm by pressing DATA: the display stops blinking, and the temperature displayed is used
for compensation.

HD2305.0 - 12 - V1.6
During manual compensation, to change the unit of measurement between °C and °F, it is nec-
essary to press twice the °C/°F key.
pH ELECTRODE CALIBRATION
The electrode calibration is used to compensate the zero potential and slope departures 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 experi-
ence, to establish the most appropriate frequency.
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 3 buffers with relevant temperature compensation tables (ATC),
one for the acid, one for the neutral, and one for the alkaline band:
@25°C
BUFR_1 (NEUTRI)
6.860
BUFR_2 (ACIDI)
4.010
BUFR_3 (ALCALINI)
9.180
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 is started by pressing CAL.
3) Among the three prepared buffers, the instrument automatically detects the closest to the pH val-
ue being read and flags it up on the lower part of the display.
If the buffer is not detected the first buffer BUFR_1 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.

HD2305.0 - 13 - V1.6
5) Press DATA/ENTER to proceed with the calibration. 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 DATA/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 pH/mV (ESC), or continue the calibration for the second
point.
7) Extract the electrode from the buffer, clean it carefully, and insert it in the following buffer.
8) Press one time the °C/°F key (MENU).
9) 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.
-a small square blinking on the lower right: electrode almost exhausted.
-two 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 DATA/ENTER at all, the calibration is interrupted by pressing
pH/mV (ESC); the previous values will continue to be used.
The buffers are always presented in the sequence set in the menu with the parameters:
-BUFR_1,
-BUFR_2,
-BUFR_3.
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 using the exact sequence BUFR_1 - BUFR_2 -
BUFR_3.
Allowed calibration sequences
Number of
calibration
points
1
BUFR_1
BUFR_2
BUFR_3
2
BUFR_1 - BUFR_2
BUFR_2 - BUFR_3
BUFR_1 - BUFR_3
3
BUFR_1 - BUFR_2 - BUFR_3
In any case where no operation is performed, the “calibration” mode automatically stops
after 60 seconds.
If the calibration is rejected by the instrument because it is considered to be excessively corrupt-
ed, the CAL ERR message will appear, followed by a long beep. The instrument remains in cal-
ibration mode and maintains the previous calibration values: at this point, if the calibration is in-
terrupted using pH-mV/ESC, the instrument signals the anomaly through the CAL message
blinking.

HD2305.0 - 14 - V1.6
Temperature characteristics of Delta OHM buffer solutions
The 3 standard buffers are memorized in the instruments with relevant variations according to tem-
perature: the characteristics of the three Delta Ohm standard buffers at 6.86pH, 4.01pH and 9.18pH
(@25°C) are reported below.
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

HD2305.0 - 15 - V1.6
4WIRE Pt100 AND 2WIRE Pt1000 TEMPERATURE PROBES
The instrument accepts the input of Platinum temperature probes with resistances of 100Ω (Pt100)
and 1000Ω (Pt1000).
The Pt100 are connected to 4 wires, the Pt1000 to 2 wires; the excitation current was chosen in or-
der to minimize the sensor self-heating effects.
All probes with SICRAM module are calibrated in the factory; the 2 or 4 wire probes with direct in-
put are checked for conformity with class A tolerance according to norm IEC751 - BS1904 -
DIN43760.
For the temperature probes without SICRAM module (Pt100 4 wires, and Pt1000) the model con-
figuration is required (please see the description of the Probe Type menu).
Temperature measurement
The response time for the measurement of the temperature in air is greatly reduced if the air is mov-
ing. 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 60 mm; 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
60 mm, the sensor is housed in the end part of the probe.
NOTE: 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 between the surface and the probe is useful (do not use water or solvents). This method
also improves the response time.
Connecting the TP47 module for the 4 wire Pt100 and 2 wire Pt1000 probes
All probes produced by Delta OHM are provided with a TP47 module.
The HD2305.0 instrument also work with direct 4 wire Pt100, and 2 wire Pt1000 probes manufac-
tured 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 TP47 module are provided below. The TP47
module is supplied complete with fairlead and gasket for 5 mm maximum diameter cables. Do the
following to open the module and connect a probe:
1. unscrew the fairlead;
2. extract the gasket;
3. remove the label using a cutter;
4. unscrew the ring on the opposite side as illustrated in the figure:

HD2305.0 - 16 - V1.6
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 weld-
ed. The JP1…JP4 jumpers are in the center of the board. These must be closed with a tin
bead for some type of sensors:
1
2
3
4
Pt1003fili
Pt1000
Ni1000
NotUsed
Caution! Before welding, pass the probe cable through the fairlead and gasket.
6. Weld the wires as shown in the table:
Sensor
TP47 board connection
Jumper to close
Pt100 4 wires
4JP4
3JP3
1JP1
2 JP2
Pt100
4 wires
None
Pt1000 2 wires
JP4
4JP3
3
JP1
1JP22
Pt1000
2 wires
JP2
Ensure the welds are clean and perfect.
7. Once the welding operation is complete, close the two shells;
8. insert the gasket in the module;
9. screw the fairlead. At the other end of the module, enter the ring with the O-Ring as indicat-
ed in the picture.

HD2305.0 - 17 - V1.6
Direct connection of 4 wire Pt100 sensors to a DIN45326 connector
4 wire Pt100 sensors can be soldered di-
rectly to the pins of the flying female
connector DIN45326 without making use
of the TP47 board. The 4 wires of the
Pt100 sensors have to be soldered as in-
dicated in the figure on the left. In order
to use this type of probe it is necessary to
set up the menu item “Probe Type” as
described at page 8. The P100 probe is
recognized upon turning on the instru-
ment: connect the probe when the in-
strument is switched off and then turn it
on. This connector does not guarantee the
IP67 protection degree.
Sensor
Direct soldering to the connector
Pt100 4
wires
View of the soldering side
of the flying female connector

HD2305.0 - 18 - V1.6
WARNINGS
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.
2. Do not bend the probe connectors or force them upward or downward.
3. Do not bend or force the contacts when inserting the probe connector into the instrument.
4. Do not bend, deform or drop the probes, as this could cause irreparable damage.
5. Always select the most suitable probe for your application.
6. Do not use the temperature probes in presence of corrosive gases or liquids. The sensor contain-
er 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
product that could corrode or damage it.
7. Above 400°C and below –40°C, avoid violent blows or thermal shocks to Platinum temperature
probes as this could cause irreparable damage.
8. To obtain reliable measurements, temperature variations that are too rapid must be avoided.
9. 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 or-
der 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.
10. Temperature measurements on non-metal surfaces usually require a great deal of time due to the
low heat conductivity of non-metal materials.
11. 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.
12. Avoid taking measurements in presence of high frequency sources, microwave ovens or large
magnetic fields; results may not be very reliable.
13. Clean the probe carefully after use.
14. The instrument is water resistant and IP67, but should not be immersed in water. 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 in-
filtration from the connectors' side.

HD2305.0 - 19 - V1.6
INSTRUMENT SIGNALS AND FAULTS
The following table lists all error indications and information displayed by the instrument and sup-
plied to the user in different operating situations:
Display indications
Explenation
>>>_PRBE_TYPE
type of probe connected
BATT TOO LOW - CHNG NOW
battery discharged - replace it immediately
BAUDRATE >>>
baud rate value
BUFR_1
first buffer value
BUFR_2
second buffer value
BUFR_3
third buffer value
CAL
LOST
Program error: it appears after turning on for a few seconds. Contact the instru-
ment's supplier.
CAL
blinking
Calibration not completed correctly.
CAL ERR
calibration error
ERR
This message appears if the pH measurement exceeds the -2.000pH…19.999pH
limits, if the mV measurement exceeds the 2.4V limits, if the temperature
probe, already detected by the instrument, is disconnected. At the same time an
intermittent beep is issued.
FUNC CLRD
max, min and average values cleared
NEW_PROB_DET
new probe detected
OFFS
offset
OVER
Measurement overflow: this appears when the probe measures a value exceed-
ing the measurement range or the mV measurement is included in the
+2.0…+2.4V range.
PLS_EXIT >>> FUNC
RES_FOR_FACT ONLY
please exit using ESC >>> function reserved to factory calibration
PRBE_SER #### ####
serial number #### #### of the connected probe
PROB
ERR
A probe with SICRAM module has been inserted when not admissible for that
specific instrument.
PROB COMM LOST
This appears if the probe, has already been detected by the instrument, but is
disconnected. At the same time an intermittent beep is issued.
SLPE%
gain %
SYS
ERR
#
Instrument management program error. Contact the instrument's supplier and
communicate the numeric code # reported by the display.
UNDR
Measurement overflow: this appears when the mV measurement is included in
the -2.4…-2.0V range.

HD2305.0 - 20 - V1.6
INSTRUMENT STORAGE
Instrument storage conditions:
Temperature: -25…+65°C.
Humidity: less than 90%RH without condensation.
Do not store the instrument in places where:
humidity is high;
the instrument may be exposed to direct sunlight;
the instrument may be exposed to a source of high temperature;
the instrument may be exposed to strong vibrations;
the instrument may be exposed to steam, salt or any corrosive gas.
The instrument case is made of ABS plastic: do not use any incompatible solvent for cleaning.
Notes on pH electrodes use
The average life of a pH electrode is about one year according to the use and maintenance per-
formed.
The electrodes used at high temperatures or in highly alkaline environments have a shorter life.
The new electrodes must be conditioned for half a day by immersing them into a buffer at 6.86pH
or 4pH.
Calibrate the electrode with solutions closer to the values being measured. A new electrode must
always be calibrated at neutral pH (6.86pH) first point and at least a second point.
Some of the most frequent problems and their possible solutions are reported below.
Wrong pH measurement. Carry out the following checks:
Check that the diaphragm is not obstructed and possibly clean it using the HD62PT solution.
Check that the reference system is not contaminated and, in case of a filling type electrode, replace
the electrolyte with the KCL3M solution.
Check that no air bubbles are present in the electrode tip and that it is sufficiently immersed.
Even dirt residuals deposited on the membrane can alter the measurement: use the HD62PP solu-
tion for protein cleaning.
Slow response or wrong measurements. Possible causes are aging or erosion of the membrane or
a connector short circuiting.
Storage. Keep the electrode immersed in the HD62SC solution.