GHM Delta OHM HD2156.1 User manual

Operating manual
Conductivity meters / pH meters /
thermometers
HD2156.1 – HD2156.2
www.deltaohm.com
English
Keep for future reference.
Companies / Brands of GHM

HD2156 - 2 - V2.5
CONTENTS
INTRODUCTION ............................................................................................................................................................ 3
KEYBOARD AND MENU DESCRIPTION .................................................................................................................. 8
PH MEASUREMENT .................................................................................................................................................... 16
AUTOMATIC OR MANUAL pH COMPENSATION .............................................................................................................. 16
PH ELECTRODE CALIBRATION ....................................................................................................................................... 17
Temperature characteristics of Delta OHM pH standard solutions ......................................................................... 20
CONDUCTIVITY MEASUREMENT .......................................................................................................................... 21
AUTOMATIC OR MANUAL CONDUCTIVITY COMPENSATION ........................................................................................... 22
CALIBRATION OF CONDUCTIVITY .................................................................................................................................. 23
Table of standard solution at 147S/cm, 1413S/cm, 12.88mS/cm and 111800mS/cm ........................................ 26
DIRECT INPUT INTO Pt100 AND Pt1000 TEMPERATURE PROBES .................................................................................... 27
How to measure ...................................................................................................................................................... 27
Instructions to connect the TP47 module for conductivity/temperature combined probes, 4-wire
Pt100 probes, and 2-wire Pt1000 probes ................................................................................................................. 27
WARNINGS AND OPERATING INSTRUCTIONS .................................................................................................. 31
NOTES ON THE USE OF THE pH ELECTRODES ................................................................................................................. 32
NOTES ON CONDUCTIVITY PROBES ................................................................................................................................ 32
INSTRUMENT SIGNALS AND FAULTS .................................................................................................................. 33
LOW BATTERY WARNING AND BATTERY REPLACEMENT ......................................................................... 35
INSTRUMENT STORAGE ........................................................................................................................................... 36
SERIAL INTERFACE AND USB ................................................................................................................................. 37
STORING AND TRANSFERRING DATA TO A PERSONAL COMPUTER ........................................................ 39
THE LOGGING FUNCTION - ONLY FOR HD2156.2 .......................................................................................................... 39
CLEARING THE MEMORY - ONLY FOR HD2156.2 ........................................................................................................... 39
THE PRINT FUNCTION .................................................................................................................................................. 40
CONNECTION TO A PC .............................................................................................................................................. 41
CONNECTION TO THE RS232C SERIAL PORT OF THE INSTRUMENT ................................................................................ 41
CONNECTION TO THE USB 2.0 PORT OF THE INSTRUMENT - ONLY FOR HD2156.2 ........................................................ 41
NOTES ABOUT WORKING AND OPERATIVE SAFETY ..................................................................................... 42
INSTRUMENT TECHNICAL CHARACTERISTICS .............................................................................................. 43
TECHNICAL DATA OF PROBES ............................................................................................................................. 47
pH ELECTRODES ....................................................................................................................................................... 47
2 AND 4-ELECTRODE CONDUCTIVITY PROBES ........................................................................................................... 47
Pt100 4-WIRE PROBES AND Pt1000 2-WIRE PROBES COMPLETE WITH TP47 MODULE .............................................. 48
ORDER CODES ............................................................................................................................................................. 49

HD2156 - 3 - V2.5
INTRODUCTION
The HD2156.1 and HD2156.2 are portable instruments with a large LCD display. They measure
pH, mV, redox potential (ORP), conductivity, liquid resistivity, total dissolved solids (TDS) and sa-
linity using combined 4-ring and 2-ring conductivity/temperature probes. Temperature only is
measured by Pt100 or Pt1000 immersion, penetration or contact probes.
The pH electrode calibration, as well as manual, can be carried out automatically on one, two or
three points and the calibration sequence can be chosen from a list of 13 buffers.
The probe calibration can be performed automatically in one or more of the 147S/cm, 1413S/cm,
12880S/cm or 111800S/cm conductivity calibration solutions.
The HD2156.2 instrument is a datalogger. It memorizes up to 20,000 sets of three measurements
composed of pH or mV, conductivity or resistivity or TDS or salinity and temperature: these data
can be transferred from the instrument connected to a PC via the RS232C serial port or USB 2.0
port. The storing interval, printing, and baud rate can be configured using the menu.
The HD2156.1 and HD2156.2 models are fitted with an RS232C serial port and can transfer the ac-
quired measurements to a PC or to a portable printer in real time.
Printing and, for the model HD2156.2, storing always include three parameters: temperature – pH
or mV – χ or Ω or TDS or g/l.
The Max, Min and Avg function calculates the maximum, minimum or average values.
Other functions include: the Auto-HOLD function and the automatic turning off which can also be
disabled.
The instruments have IP66 protection degree.
This manual describes the HD2156.1 and HD2156.2 models: if not otherwise specified, the de-
scription is intended to be applicable to both models.

HD2156 - 4 - V2.5
Conductivity meter – pH meter – Thermometer
HD2156.1

HD2156 - 5 - V2.5
HD2156.1
1. BNC connector for the pH/mV electrode.
2. 8-pole DIN45326 connector, input for combined 4-ring or 2-ring conductivity/temperature
probes, for direct 4-wire Pt100 temperature probes and 2-wire Pt1000 probes complete with
TP47 module.
3. External auxiliary power supply connector input (positive at centre).
4. Battery symbol: displays the battery charge level.
5. Function indicators.
6. Secondary display line.
7. CAL/ key: during normal operation starts the conductivity probe or pH electrode calibration;
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 se-
lection. This updates the display measurement when the Auto-Hold function is enabled.
9. pH/mV-ESC key: changes the main variable measurement between pH and mV. In the menu,
confirms the current selection.
10. SERIAL key: starts and ends the data transfer to the serial communication port.
11. MENU key: allows access to and exit from the menu.
12. χ-Ω-TDS/ESC key: changes the main variable measurement between conductivity, resistivity,
total dissolved solids (TDS) and salinity. In the menu, cancels the operation in progress without
making changes.
13. °C/°F key: when the probe is not connected, allows manual modification of the temperature.
When the probe is connected, if this key is pressed twice, it changes the unit of temperature
measurement from degrees Celsius to Fahrenheit.
14. ON-OFF/AUTO-OFF key: turns the instrument on and off; when pressed together with the
CAL key, disables the automatic turn off.
15. pH electrode efficiency indicators.
16. MAX, MIN and AVG symbols.
17. Main display line.
18. Line for symbols and comments.
19. 8-pole MiniDin connector for RS232C. For the connection to PC (with cable HD2110CSNM or
C206) or printer (with cable HD2110CSNM).

HD2156 - 6 - V2.5
Conductivity meter – pH meter – Thermometer
HD2156.2

HD2156 - 7 - V2.5
HD2156.2
1. BNC connector for the pH/mV electrode.
2. 8-pole DIN45326 connector, input for combined 4-ring or 2-ring conductivity/temperature
probes, for direct 4-wire Pt100 temperature probes and 2-wire Pt1000 probes complete with
TP47 module.
3. External auxiliary power supply connector input (positive at centre).
4. Battery symbol: displays the battery charge level.
5. Function indicators.
6. Secondary display line.
7. CAL/ key: during normal operation starts the conductivity probe or pH electrode calibration;
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 se-
lection. This updates the display measurement when the Auto-Hold function is enabled.
9. pH/mV-ESC key: changes the main variable measurement between pH and mV. In the menu,
confirms the current selection.
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. MENU key: allows access to and exit from the menu.
14. χ-Ω-TDS/ESC key: changes the main variable measurement between conductivity, resistivity,
total dissolved solids (TDS) and salinity. In the menu, cancels the operation in progress without
making changes.
15. °C/°F key: when the probe is not connected, allows manual modification of the temperature.
When the probe is connected, if this key is pressed twice, it changes the unit of temperature
measurement from degrees Celsius to Fahrenheit.
16. ON-OFF/AUTO-OFF key: turns the instrument on and off; when pressed together with the
CAL key, disables the automatic turn off.
17. pH electrode efficiency indicators.
18. MAX, MIN and AVG symbols.
19. Main display line.
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).

HD2156 - 8 - V2.5
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 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 ena-
bled.
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.
The following can be seen on the display at the same time:
1. pH (or mV) and temperature
2. conductivity (or resistivity or total dissolved solids or salinity) and temperature.
It is not possible to see pH (or mV) and conductivity at the same time: one measurement or
the other must be selected using the "pH/mV - " and "χ-Ω-TDS/ESC" keys. In direct print
and when logging three quantities are captured at the same time: pH/mV, conductivity and
temperature.
ON-OFF/Auto-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, and displays the current values of cell constant (CELL) and
temperature coefficient  (ALPH). Finally, the instrument is set in standard working mode, dis-
playing the measurement which remained enabled at the last turning off in the main line, and the
temperature in the secondary line.
MIN
cm
min s
2
3
mµ
m
k
>>>
During turning on, should no probes be connected, 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.
The probe's data are captured upon turning the instrument on: if the ERR message appears
in the secondary line, it is necessary to turn the instrument off and then on again.
Replace the probes when the instrument is off.

HD2156 - 9 - V2.5
+
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 disa-
bled by holding the CAL/ 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 and logging of the maximum (MAX), mini-
mum (MIN) and average (AVG) value of the pH, mV, conductivity, liquid resistivity, total dis-
solved solids, salinity and temperature measurements, updating them with the acquisition of new
samples. The acquisition frequency is once a second.
To switch from pH to mV, press the "pH/mV-" key. Use the χ-Ω-TDS/ESC key to switch from
conductivity to liquid resistivity, to total dissolved solids or to salinity.
In the menu, the ENTER key confirms the current parameter and then goes to the next one.
The MAX, MIN and AVG measurements remain in the memory until the instrument is on, even af-
ter exiting the calculation function. 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.
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 below.
Attention: the data captured using the Record function cannot be transferred to the PC.
CAL/ key
It increases the current parameter when used in the menu; when used in measurement mode, it starts
the displayed variable (pH or conductivity) calibration (please see the chapter dedicated to pH, page
17, and conductivity, page 23, calibration).
°C/°F key
When a probe with temperature sensor is connected, the key changes the unit of measurement from
degrees Celsius to Fahrenheit. The measured temperature value is used to compensate the pH or
conductivity measurement.
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

HD2156 - 10 - V2.5
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 the temperature
displayed 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.
χ-Ω-TDS (conductivity - resistivity - total dissolved solids - salinity) / ESC key
Changes the main variable measurement between conductivity, resistivity, total dissolved solids
(TDS) and salinity. The selected parameter is used for display, printing, and logging.
In the menu, the key clears or cancels the active function (ESC).
Auto-HOLD function
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 digit) for over 10 seconds: the message
HOLD is displayed.
To perform a new measurement, it is necessary to press the FUNC/ENTER key.
The HOLD message starts blinking, while the display follows the actual measurement trend, until it
stabilizes again and the HOLD message remains still.
pH/mV -  key
Changes the main variable measurement between pH and mV. The selected parameter is used for
display, printing, and logging.
Auto-HOLD function
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 FUNC/ENTER key.
The HOLD message starts blinking, while the display follows the actual measurement trend, until it
stabilizes again and the HOLD message remains still.
NOTE: when the Auto-Hold function is enabled, the measurement in mV is disabled. To restore
the display in mV, disable the Auto-Hold function in the menu.
When used in the menu, it decreases the current variable value.
MENU Key
The first menu item is accessed by initially pressing on the MENU key; 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. If pressing
ESC, the setting is cancelled.
To exit the menu, press the MENU key at any time.