Observator Instruments ANALITE NEP160 User manual

ABN 56 007 283 963
8 - 10 Keith Campbell Court, PO Box 9039, Scoresby, Australia, 3179
Tel: [phone], Fax: [phone]
www.observator.com [email protected]
User Manual
Analite NEP160
Portable Turbidity Meter

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 2 of 24

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 3 of 24
160 SERIES
MICROPROCESSOR BASED TURBIDITY METER
The ANALITE 160 turbidity meter is the latest of our range of turbidity measurement instruments.
It is designed to operate with either an ANALITE retro-scatter (180°) probe or an ANALITE
ISO7027 90° probe. The ANALITE 160 turbidity meter allows the user to set up measurement
parameters through a user-friendly menu system displayed on the in-built 2 line alphanumeric
display.
Measurements can be read directly from the display at any time or downloaded to a computer/printer
through the RS232 output at user selectable periodic intervals.
The NEP160 will power up automatically to its last settings whenever external power is applied
making it ideal for logging applications when using the analogue output or RS232 port.
A NEP160 shown complete with ANALITE NEP260 probe.
(part number NEP160-3-05-R)

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 4 of 24
Specifications
Range: 0 to 30,000NTU (3,000NTU limit on NEP260, 90° probe)
(over four ranges automatically determined).
Display: 2 line, 16-character dot matrix alphanumeric liquid crystal display.
Display Language: English.
Parameters Displayed: Turbidity (NTU) - default
Relative Turbidity Reference (NTU)
Relative Turbidity REL (Turbidity - Relative Turbidity Reference)
Date/Time - default
Reading: Updated approximately every 1 second.
Averaging period: 0.5 second or 8 seconds nominal –user selectable.
Auto Range Steps: 1 <0.1 to 20NTU
2 <1 to 200NTU
3 <10 to 2,000NTU
4 <100 to 20,000NTU (using NEP280, 180° probe only)
Resolution 1 0.02NTU
2 0.1NTU
3 1NTU
4 10NTU
Repeatability: 2% ± 1 digit on all ranges.
Data Logging: User set for one reading every 1 to 90 seconds or minutes. All readings
stored in the Notepad.
Notepad: 100 readings each with time and date.
Setup Procedures: Menu driven, including:
–Calibration
–Automatic Logging
–Analogue Output range selection
–Reference Turbidity value
–Setting date and time.
Setup Memory: Non volatile EEPROM.
Clock: Calendar clock displays date and time.
Good Laboratory Practice: All readings as well as calibration constants are stored together with
the Time and Date and can be recalled at any time.

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 5 of 24
Analogue Output 0 –2 volts full scale corresponding to preset measurement range.
Output impedance 600 ohms nominal.
Power: Internal: 6V NiMH rechargeable battery.
External: 10 to 16V dc, 400mA max. incl. NiMH Charge current.
External power connection is via jack plug male with 2.5mm pin.
Centre pin is NEGATIVE polarity.
Power Management: Automatic power down when operating from batteries after approx. 5
minutes may be selected. Automatic power up when powered
externally.
Continuous operation of at least 5 hours on a fully charged battery.
For normal intermittent operation a full charge may last several days.
Low battery indication prior to shut down.
Measurement Outputs: Inbuilt LCD, analogue output and RS232 port.
RS232 Port : The RS232 port can output readings on request or at preset intervals of
time from 1 to 99 seconds or minutes. The Notepad memory can also
be downloaded on request.
4800 baud rate, 8 bits, no parity, 1 stop bit, Xon/Xoff protocol.
Dimensions: 187mm x 110mm x 51mm (display unit).
Weight: Display Unit 0.5kg.
180° Probe 0.4kg with 5m lead.
90° Probe 0.4kg with 5m lead.
Operating Temperature: 0° to 50°C.
Operating Humidity: 0 to 90% R.H.
Storage Temperature -10° to 60°C.
Case Rating: IP65 with all connectors sealed with dust caps (supplied) or probe
properly connected and dust caps on remaining two connectors.
Ordering Information: NEP160R Display unit only.
NEP160-1-05R NEP160 with general purpose NEP280 -180° probe.
NEP160-2-05R NEP160 with high temperature NEP285 -180° probe.
NEP160-3-05R NEP160 with NEP260 –ISO7027, 90° probe.
All probes are supplied with 5 meters of cable unless otherwise
indicated at time of order.

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 6 of 24
NEP160 Display and Controls
Packaging Information
The following are included with every ANALITE NEP160 purchased:
1. The NEP160R Turbidity Meter Display Unit
2. The NEP160 Operation Manual
Depending on your order, some or all of the following may also be included:
1. Turbidity Probes (see below).
2. RS232 Interface and External Power cable assembly.
3. Battery charger lead for 12V automotive cigarette lighter socket.
4. Turbidity Standards Solutions (10, 40, 100, 400, 1000NTU).
5. AC adapter and battery charger (7PSU-2).
6. NEP16SHRD protective stainless shroud for the NEP260 probe.
Spares readily available include:
1. 6V NiMH Battery Unit.
1. F1 Press to record readings into memory.
2. F2 Press to show or hide the date and time.
3. F3 Press to view logging status or start or stop
automatic logging.
4. F4 Prints current reading to the RS232 port.
5. Menu Press to access the user-friendly menu
system, which makes using the NEP160 a
breeze to operate.
6. and 8. 
These keys are used when calibrating,
setting the clock, or setting the automatic
logging period and RS232 reading output
interval.
7. Switches the NEP160 ON and OFF.
9. Display. 32-character alphanumeric liquid crystal
display with user-friendly menu and
prompting system. Displays turbidity and
the date/time simultaneously.
ON
OFF
NEP160 Turbidity Meter

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 7 of 24
Three turbidity probes are available that suit the NEP160R Turbidity Meter. They are:
ANALITE NEP280 General Purpose retro-scatter probe capable of measuring turbidity level from
10 to 30,000NTU. The NEP280 can be submersed to a depth of 30m.
Standard cable length is 5 meters unless otherwise indicated at time of order.
ANALITE NEP285 High temperature retro-scatter probe capable of measuring turbidity level
from 10 to 30,000NTU. The stainless steel probe shaft uses glass fibre optics
and can sustain temperature of up to 125°C. The NEP285 can be submersed
to a depth of 30m. Standard cable length is 5 meters unless otherwise
indicated at time of order.
ANALITE NEP260 High sensitivity 90° probe to ISO7027 capable of measuring turbidity levels
from 0 to over 3,000NTU. The NEP260 can be submersed to a depth of 30m.
Standard cable length is 5 meters unless otherwise indicated at time of order.
All the above probes have stainless steel housings and are normally supplied with a 5m cable and
connector suited to the NEP160. Longer cable lengths can be accommodated but must be specified at
time of order.
For more details on these probes contact your local ANALITE distributor or contact Observator
Instruments.
Charging the NEP160 Internal Battery
1. Remove the dust cover on the External Power and RS232 Port connector on the NEP160R
display unit.
2. Connect the multi-pin connector of the RS232 Interface and External Power cable assembly
to the External Power and RS232 Port connector on the NEP160R display unit.
3. Connect the AC adapter output cable to the mating connector on the RS232 Interface and
External Power cable assembly.
4. Plug the mains cable into the PSU-2 power supply and connect to the local mains supply.
Charging should commence immediately but it may take a few seconds for this to be
indicated on the NEP160R display.
Normal Operation
In Normal Mode pressing the Functions keys perform the following tasks:
F1 Press to record the current data plus date and time into the notepad.
F2 Press to show or hide the date and time on the display.
F3 Press to view logging status or start and stop automatic logging.
F4 Transmits (prints) the current reading to the RS232 port.

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 8 of 24
Operating the NEP160
Probes
The probes designed to operate with the NEP160 display units are "smart probes" in that they each carry their own
"signature", that is, calibration and characterization data. Consequently, probes can be connected to any NEP160 and the
display unit is immediately informed of the necessary calibration constants for proper operation. This allows the operator
to use more than one probe with the same display unit. Further, Observator Instruments can periodically calibrate the
probes without the need to return the NEP160 display unit.
On power up the NEP160 will interrogate the probe socket to determine if a probe is connected and its parameters. If a
probe is not connected the display will show:
SEEKING PROBE
After successful interrogation of a probe the display will show for a short period:
PROBE S/N xxxxx
Where xxxxx is the probe's serial number. This proves successful communication with the probe. Probes may be changed
over at any time. Immediately another probe is connected the display will indicate the serial number of the probe to show
proper communication has taken place and the NEP160 has the necessary probe information for accurate readings.
The NEP160 has two operating modes: absolute turbidity and relative turbidity. The default mode is absolute turbidity
Absolute turbidity displays the actual solution turbidity in NTU, whereas relative turbidity indicates the relative
difference of the measured solution against some preset reference solution or NTU reference.
Normally the NEP160 will show the absolute value. This is evident on the top line of the display in that it is simply
shown as NTU.
E.g. 700NTU
When in the Relative Turbidity mode the measured value is followed by the REL icon,
E.g. 700NTU REL
Pressing F2 when in the Relative Turbidity mode will sequence the second line of the display to show:
a blank line,
the time and date, or
the current Reference NTU value.
Normal day to day operation of the NEP160 is as simple as turning it on and start measuring. When a measurement is
satisfactory press F1 to place the reading into memory for later retrieval. The time and date may be toggled on and off by
merely pressing the F2 key.
The NEP160 uses Good Laboratory Practices (GLP) by recording each measurement into memory with the time and date.
Calibration constants are also tagged with the time and date of last alteration.
The following sections describe how to set up the NEP160 through its user-friendly menu structure. Once set up the
NEP160 offers an ease of measurement not known before in such a powerful portable turbidity instrument.
Battery Care and Maintenance
The ANALITE NEP160 is fitted with a NiMH battery that is charged using the in-built controller to maximise life and
operating time between charges.
When shipped the battery will be in a discharged state and will require at least 12 hours charging before use. Thereafter a
full charge will be achieved in less than 5 hours of charging.

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 9 of 24
If the instrument is to be stored for a long period of time (say more than 4 weeks), then it is best to fully charge the
battery before storage and then recharge again for 12 hours prior to use. A few charge cycles may be required after
extended periods of storage to properly reform the cells.
As shipped, the NEP160 is configured to shutdown after approximately 5 minutes when operating from internal battery
power.
RS232 Port
The NEP160R is supplied with an integrated RS232 port. The External Power and RS232 Port connector on the
NEP160R is a shared connector. To connect the NEP160R to a PC COM port you will need to connect the multi-pin
circular connector of the RS232 Interface and External Power cable assembly supplied to the NEP160R and the DB9
connector on the cable assembly to a PC COM port (DB9 connector). The external power connector on the cable
assembly may be connected to the AC adaptor (7PSU-2) to charge the internal NEP160R batteries.
More recent PCs may not have COM ports in which case a RS232/USB converter (not supplied) will be required to
connect to the PC via a USB port.
Communication and data transfer between the NEP160R and the PC is done using communication software such as
Windows®HyperTerminal.
Sending readings to the RS232 Port
Press F4 when in normal display mode to send current reading to the RS232 port.
Readings can be sent directly to the RS232 port rather than stored in the Notepad memory during
automatic logging (see section F4.4).
RS232 Protocol
The NEP160 RS232 protocol is 8 bits, no parity, 1 stop bit, Xon/Xoff at fixed 4,800baud.
RS232 Port Commands
The following commands can be sent to the NEP160 RS232 port.
<cr> denotes a carriage return and <lf> a line feed.
Action
Command
Notes
Request current reading
?D<cr>
Returns the current turbidity reading, mode, date and
time. The log number returns is set to zero.
Data format A.
Request logged
readings
?R<cr>
Returns all logged records from the Notepad. The data
ends with the message ENDS<cr>.
Data format B.
Erase logged readings.
?E<cr>
Erases all logged readings from the NEP160 Notepad
memory. Returns the message ERASED<cr> to
confirm that all records have been erased.
Request status
information
?S<cr>
Returns the model name, the Reference NTU value and
number of logged readings in the Notepad.
Data format D.
Request instrument
information
?W<cr>
Returns the firmware version in the NEP160 followed
by the display and probe (if attached) serial numbers.
Data format E.

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 10 of 24
RS232 Port Data Format
Format
Structure
Notes
A
dd/mm/yy_hh.mm.ss_LLL_DDDDDD_NTU_MMM<cr><lf>
?D<cr>
B
dd/mm/yy_hh.mm.ss_LLL_DDDDDD_NTU_MMM<cr><lf>
ENDS<cr>
?R<cr>
C
dd/mm/yy_hh.mm.ss_LLL_DDDDDD_NTU_MMM<cr><lf>
Automatic logging to
RS232
(see section F4.4)
D
NEP160___999_RRRRRR<cr><lf>
999 number of logged
readings right justified.
E
NEP160_Vx.x_D#####_P#####<cr><lf>
D = display serial no.
P = probe serial no.
Where:
_ represents a space
LLL is the log number, maximum 3 characters, right justified.
LLL is always 000 when requesting the current reading using the ?D command.
DDDDDD is the turbidity data, 6 characters including sign and decimal place, right justified.
RRRRRR is the Reference NTU value, 6 characters including sign (always positive) and decimal
place, right justified
NTU is the text NTU to indicate the unit of measurement.
MMM is the measurement mode: ABS for absolute data or REL for relative data.
dd/mm/yy is the date/month/year each two digits.
Where the date format is mm/dd/yy (see section F4.2) the format would be mm/dd/yy.
hh:mm:ss is the time in hours:minutes:seconds format based on a 24 hours clock.
999 represents the total number of logged readings in the Notepad.
x.x is the software version number, 3 characters with the middle being a period.
##### represents a serial number, 5 characters, right justified.
ANALink 2 PC Software
A simple MS Windows based program called ANALink 2 is available from Observator Instruments.
ANALink 2 allows simple interfacing between an ANALITE NEP160 and a PC operating
Windows 95/98/NT/2000/XP/7. The program is approximately 2.5Mbytes in size.
ANALink 2 allows all commands to be sent to the NEP160 with the results shown on the PC display
as well as immediate and logged turbidity readings
No claims or warranty is offered on the ANALink 2 program and is made available only on an “as-is”
basis. Observator Instruments claims copyright on the ANALink 2 PC software.

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 11 of 24
NEP160 Menu Structure
A quick reference of the NEP160 operation structure is shown below. Pressing the Menu key evokes the menu structure.
Each of the Menu Functions is described in detail elsewhere.
Power ON
Copyright
Message
NORMAL
NTU Measurement
Display
MENU
MODE
MENU
Store to
Notepad
Toggle
Display
Logging
ON/OFF
Output to
RS232
(optional)
CALIBRATE
NOT EPAD
MODE
SETUP
MENU
F1
F2
F3
F4
F1 Battery
F2 Date/Time
F3 Analog O/P Span
F4 Logging Interval
F1 Absolute NTU
F2 Relative NTU
F3 AVG - ON/OFF
F4 Ref Types
F1 Recall Data
F1 Numeric
F2 Solution
F2 Erase Data
F3 Output Data
F1 Probe Data
F2 2 Point Cal.
F3 3 Point Cal.
Set Time
Date Format
Data to
Notepad/RS232
F1
F2
F3
F4

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 12 of 24
F1 Calibration
The probe connected to the NEP160 display unit will determine how the information collected is displayed. But in every
case the mathematical treatment is the same as shown schematically below:
Standard Curve
Algorithm
px
3
+qx
2
+rx
(stored in NEP160
Display Unit
- factory set)
Temperature
Compensation
(NTU/°C)
(stored in NEP160
Display Units
- factory set)
y
L
Probe Calibration
Algorithm
y = bx + c ( 2 point)
y = ax
2
+ bx + c (3 point)
(Stored in probe
- user set)
y
t
Internal Probe
Temperature
Three standard curve algorithms are stored in the NEP160:
1. NEP260 - 90° probe (3,000NTU max)
2. NEP280 - 180° probe (30,000NTU max)
3. NEP900 - Custom probe (custom software)
Data (x)
from
Probe
Result (y)
to display
processing
The probe attached to the NEP160 can be calibrated at any time using a two point or three point technique. When
calibration is complete the time and date of the calibration will also be recorded against the calibration constants.
Probe information including the current calibration constants can be reviewed at anytime.
Calibration Practices
Because a turbidity probe is inherently an optical device, care must be taken during calibration to ensure that external
effects are kept to a minimum. This is best implemented by placing calibration solutions in dark, leakproof bottles with a
non-reflective finish such as Nalgene®2106 bottles in amber. These are available with wide necks and a nominal capacity
of 1,000ml.
Another important factor is cleanliness. Any debris or water that makes its
way into the calibration solutions will affect its value and adversely affect
the proper calibration of an instrument. It is therefore a good practice to
have an ample supply of distilled de-ionized water and a means of
properly drying the probe end (clean compressed air is ideal). Probes
should be flushed in two containers of distilled water with thorough
drying in between and before insertion into a calibration solution. Also
calibration should commence at a lower value (usually zero) and work up
in value to further minimize the effects of cross contamination.
Analite turbidity probes are best calibrated using AMCO Clear solutions,
as they are stable and safe. Other solutions may be used such as formazin
but these are normally not as stable and should be treated with caution as
they may contain carcinogens.
When inserting the ANALITE probe into the calibration solution ensure
that the optic face of the probe is at least 50mm from the base and all sides of the bottle. This is particularly important for
low turbidity solutions below 200NTU. Hold the probe a few degrees from the vertical and gently tap it on the bottle rim
so as to dislodge any air bubble on the optic face. If the probe is properly placed the value indicated will not vary if the
probe is gently moved a few millimeters in any direction.

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 13 of 24
F1.1 Reviewing Probe Information
Select the Setup menu by pressing Menu and then F1.Cal
Select F1 Probe
The display should now look something like this:
Type NEP260
S/N 76340 F2:>
Press F2 to see the date and time of the last probe calibration.
24/02/99 13.38
FACTORY F2:>
The display will indicate “FACTORY” if the last calibration was a factory calibration during
manufacture or “USER” if the last calibration was done after the factory calibration.
Press F2 to see the last user calibration date and time.
24/02/99 13.38
FACTORY F2:>
Press F2 select which calibration constants will be used.
Use user cal
:set F2:>
Use  to toggle from factory calibration constants to user calibration constants
1
2
3
4
5
7
Press F2 to quit and implement selected calibration constants and return to normal operation

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 14 of 24
F1.2 Calibration - 2 point
A two-point calibration is normally all that is needed when the anticipated results are centred about a common value (e.g.
80NTU). Under these circumstances it is best to calibrate the second point near or just above the anticipated readings. In
the above example 100NTU would be a good second calibration point.
1
Connect the desired Probe to the ANALITE NEP160 Turbidity Meter
2
Press the ON button to power the ANALITE NEP160 ON.
3
Select the Setup menu by pressing Menu and then press F1.Cal
4
Select F2 2pnt
Place the Probe into a 0NTU solution reference solution. Ensure proper calibration procedures are met.
The display should now look like this:
x.xxNTU pnt 1/2. (where x.xx is a low number).
Wait until the reading settles and stabilizes.
“Grab” the zero by pressing the F2 button, F2:grab
Comment: The NEP160 assumes that the first point of any calibration is always ZERO NTU
5
The display should now look like this:
0.00NTU pnt 1/2
Press F2 to accept the new zero value, store it and move to the second calibration point.
(F2:OK).
Comment: When the F2 button is pressed it is normal for the display to return to the original reading
and not zero NTU.
6
Remove the probe from the 0NTU standard reference solution and dry off the probe.
Place the probe into a known turbidity standard solution (eg. 100NTU)
The display will now look like this:
xxx.xNTU pnt2/2 (where xxx.x is a value near to 100).
Wait until the reading settles and stabilizes, then grab the stabilized value by pressing the F2 button.
(F2:grab)
7
The display will now look like this: xxx.xNTU pnt2/2
8
Use the  buttons to adjust the displayed reading to match the value of the turbidity standard
solution e.g. 100.
9
Press F2 to select the selected calibration constant, quit and return to normal operation.
Comment: When F2 is pressed the display will return to the calibrated NTU reading, e.g. 100±0.5NTU
typically.
10
Remove the Probe from the second reference solution, wash in de-ionized water and dry.
11
This completes a two-point calibration process.

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 15 of 24
F1.3 Calibration - 3 point
A three-point calibration is recommended when operating the ANALITE NEP160 over a wide range (say 0 to
10,000NTU) or where exceptional linearity is demanded over a nominal range (say 0 to 100NTU). For purposes of
example only, we are using 50NTU and 100NTU as the calibration reference solutions when explaining the three-point
calibration procedure below. Normal practice would be to select a second point value at the anticipated values of
measurement and the third point of calibration being the highest measurement value anticipated (or a little higher).
1
Connect the desired Probe to the ANALITE NEP160 Turbidity Meter
2
Press the ON button to power the ANALITE NEP160 ON.
3
Select the Setup menu by pressing Menu and then F1.Cal
4
Select F3 to select the 3 point calibration.(F3:3pnt)
5 Place the Probe into the 0NTU standard reference solution.
The display should now look like this:
x.xxNTU pnt1/3 (where x.xx is a low number)
Wait until the reading settles, then “grab” the zero reference by pressing F2
(F2:grab)
Comment: The NEP160 assumes that the first point of calibration is always ZERO NTU.
6
The display should now look like this:
0.00NTU pnt1/3
Press the F2 button to accept and store the zero value and move to the second calibration point
(F2:OK)
Comment: When the F2 button is pressed it is normal for the display to return to the original reading,
i.e. not zero.
7
Remove the Probe from the 0NTU solution and dry the Probe.
8
Place the probe into a known turbidity standard solution (e.g. 50NTU)
The display will now look like this:
xx.xNTU pnt2/3 where xx.x is normally a value near to 50.
Wait until the reading settles, then “grab” the stabilized value by pressing F2
(F2:grab)
9
The display will now look like this:
xx.xNTU pnt2/3
10
Use the  buttons to adjust the displayed reading to match the solution value reading e.g. 50.
11
With the display adjusted press F2 to accept and store the reading and move to the third calibration
point.
Comment: When F2 is pressed the display will return to the original NTU reading.
12
Remove the Probe from the 50NTU solution, wash in de-ionized water and dry.
13
Place the probe into a known turbidity standard solution (e.g. 100NTU)
The display will now look like this:
xx.xNTU pnt3/3 where xx.x is normally a value near to the value of the turbidity standard
solution e.g.100.
Wait until the reading settles, then “grab” the stabilized value by pressing F2
(F2:grab)
14
The display will now look like this:
xx.xNTU pnt3/3
15
Use the  buttons to adjust the displayed reading to match the solution value reading e.g. 100.
16
With the display adjusted press F2 to accept and store the reading and exit calibration.
Comment: When F2 is pressed the display will return to the calibrated NTU reading e.g. typically
100±1NTU.
17
Remove the Probe from the 100NTU solution, wash in de-ionized water and dry.
18 This completes a three-point calibration.

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 16 of 24
Notes on Calibration
The NEP160 measures turbidity in NTU. Other units often used are FTU, JTU (Jackson Turbidity Unit) and mg/L
(suspended solids). The conversion table below shows the relationship between these units.
NTU
FTU
JTU
mg/L (SiO2)
NTU
1
1
0.053
0.13
FTU
1
1
0.053
0.13
JTU
19
19
1
2.5
mg/L (SiO2)
7.5
7.5
0.4
1

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 17 of 24
F2 Notepad Function
F2.1 Recording Readings into the Notepad.
To record readings into the Notepad memory:
1
Press F1 in normal display mode. The display should change to show typically:
700NTU #005
F1:Yes F2:No
The top line of the display indicates the reading 700NTU and the following characters #005 indicates the
record number of the reading. On the bottom line, the F1: indicates wish to continue, and the F2 : to quit
recording
2
If you press F1 again, the turbidity reading, time and date will be recorded into the Notepad and labeled
as record number 5.
If you press F2, the recording of the reading will be aborted with a return to NORMAL operation.
3
Repeat steps 1 and 2 as often as required. The maximum number of readings that can be stored is 100.
F2.2 Recalling Records from the Notepad.
To recall records from the Notepad memory.
1
Select the Notepad menu by pressing Menu and then F2.
2
Select Recall F1 from the menu.
3
Record number 1 is now displayed, typically:
700NTU
#001 F2:more 
4
Press F2 to toggle display between time and date or the data for this record.
5
Press and to move forward or back through the records. Press and hold and to scroll
rapidly through the records.
F2.3 Erasing Records from the Notepad
To erase all records from the Notepad memory.
1
Select the Notepad menu by pressing Menu and then F2.
2
Select Erase F2 from the menu.
3
The NEP160 now asks if you are sure you wish to erase all the records.
Erase, You Sure?
F1:Yes F2:No
4
Press F1 to erase all records from the Notepad or F2 to quit without erasing records.
F2.4 Printing Records from the Notepad to the RS232 Port
This function is only available when the RS232 port is fitted.
1
Connect the plug of the RS232 cable into the Charger/RS232 socket of the NEP160. The charger or
optional car battery lead can be connected into the socket of the RS232 cable if required.
2
Connect the DB9 socket on the RS232 cable to an RS232 printer, or to COM1 or COM2 of a PC.
3
Ensure that the baud rate setting of the printer or PC is the same as that set for the NEP160 (4,800baud).
The NEP160 uses Xon/Xoff protocol, so ensure the printer or PC is set accordingly.
4
Select the Notepad menu by pressing Menu then F2.
5
Select F3 Print from the menu. The word Printing is displayed until the transfer to the printer
or PC is completed.

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 18 of 24
F3 Mode
F3.1 To set Absolute Turbidity measurement mode.
1
Select the Mode menu by pressing Menu and then F3.
2
Select F1 Abs NTU
3
Display will revert to normal, and all measurement will be in absolute NTU. This is confirmed by
ensuring the displayed measurements are not followed by the characters REL
F3.2 To set Relative Turbidity measurement mode
1
Select the Mode menu by pressing Menu and then F3.
2
Select F2 Rel NTU
3
Display will revert to normal, and all measurement will be in relative NTU. This is confirmed by
ensuring the displayed measurements are followed by the characters REL
F3.3 To set up the Reference NTU value.
The reference NTU value is the reference point from which all Relative Turbidity measurements are made. If for example
the reference is set up as 100NTU, then the display will show -10NTU REL in a 90NTU solution and +10NTU
REL in a 110NTU solution. The default value is 0NTU when supplied from the factory.
The Reference NTU value can be read at any time during measurement in the relative mode by pressing F2.
1
Select the Mode menu by pressing Menu and then F3.
2
Select F4 SET Ref If you know the NTU value you want set as a reference select F1 Number or
F2 Soln Ref if you wish to use an actual solution as a reference.
3
If F1 Number is selected. Select the digit to be set using F1 or F2, change the digit value by pressing
and . Press and hold and to scroll rapidly to the desired value. Continue the above steps
with each digit until the desired Reference NTU value is displayed. Pressing F2 after all digits have
been set, will scroll the cursor to the right and exit. This will store the reading as the Reference NTU
value.
If F2 is selected, place the probe into the solution and allow the reading to stabilize. Pressing F4 will
store the reading as the Reference NTU value. To cancel the operation, press Menu , the NEP160 will
quit and revert to normal display mode
4
The NEP160 will revert to normal display mode.

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 19 of 24
F4 Setup
F4.1 Battery Saver
The NEP160 is equipped with a battery saver function. When operating under battery power and if no button has been for
approximately five minutes, the unit will beep and the display will flash for 20 seconds, thereafter it will shut off. This
function can be disabled for continuous use under battery power.
To enable or disable the battery saver function:
1
When in normal display mode select Setup by pressing Menu and then F4 Setup
2
Select F1 Batt
3
The display now indicates battery and battery saver status, typically:
Batt Saver ON 
F1:OK
The ON indicates the current battery saver selection. The bar graph indicates the approximate level of
charge remaining in the battery.
4
Press  to toggle the battery saver function.
5
Press F1 to quit the battery saver function in the mode indicated.
6
The battery bar graph will flash when the battery voltage falls below 5.5V. At 5.0V the NEP160 will
automatically shut itself down.
Comments on battery care.
The battery in the NEP160 is a 5-cell NiMH unit. When you first receive the NEP160 or after an extended period of
storage the instrument it should be charged for at least 12 hours to allow proper forming and charging of the cells.
The state of battery charge is best read with the AC adapter disconnected. After disconnecting the AC adapter and with
the NEP160 switched on, press Menu, then F4 (setup) and then F1 (Battery). The battery charge status will be shown.
From time to time it is desirable to cycle the battery from complete discharge to charge to ensure it maintains its energy
capacity. This is implemented by firstly turning OFF the Battery Saver feature and then leaving the instrument on until
the battery is discharged. Recharge the instrument. After long periods of inactivity this procedure may need to be done
two or three times to re-establish the battery’s energy capacity. The battery life is nominally 2 – 3 years with regular use.
F4.2 Clock
Selecting the Date Format
The NEP160 allows the date to be expressed in either dd/mm/yy or mm/dd/yy format.
1
When in normal display mode select Setup by pressing Menu and then F4 Setup
2
Select F2 Clock
3
The display now shows the current date and time. Typically:
dd/mm/yy hh:mm
:Set F1< F2>
4
If the date format is not as required press format the and keys to toggle the format. The
date format should be seen to change accordingly.
5
Press Menu to exit with displayed format and return to the normal display mode,
Or F2
If setting of the clock is required
!!!!!
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>

NEP160 User Manual
Copyright –2000 - 2011
Specifications subject to change without notice.
Page 20 of 24
31/12/97 12:00
:Set F1< F2>
The cursor starts under the day.
4
Press the and keys until the day is correct.
5
Press F2 to move to the month. Press the and keys until the month is correct.
6
Press F2 to move to the year. Press the and keys until the year is correct.
7
Press F2 to move to the hour. Press the and keys until the hour is correct.
8
Press F2 to move to the minutes. Press the and keys until the minutes are correct.
9
Check that the date and time are correct. Press F2 to save the settings. If changes are
required, press the F1 key to move left to the desired position.
10
Press Menu to return to the normal display mode.
Displaying or Hiding the Clock
The date and time are normally displayed along with the turbidity readings. Press F2 in normal display mode
to alternatively display or hide the clock display. When in Relative Turbidity mode, pressing the F2 key will
include in the sequence the current Reference NTU value.
F4.3 Setting the Analogue Output range
The analogue output has a full-scale output of 2.0V corresponding to the range selected. The available ranges
are 20NTU, 200NTU, 2,000NTU and 20,000NTU.
1
Select the Setup menu by pressing Menu and then F4 Setup
2
Select F3 Analog and the current full scale value will be displayed.
3
Press the and keys until the desired full scale range is displayed (20, 200, 2,000 or
Setting the Clock
1
When in normal display mode select Setup by pressing Menu ,
then F4 Setup, and then F2 Clock
2
Select F2 from the Date format display
3
The display now shows the current date and time. Typically:
<
>
20,000NTU)
4Press to accept the desired range and return to the normal display.
F2