Newport 843-R User manual

97x210mm
LASER POWER METER
USER MANUAL
843-R
843-R
NEWPORT CORPORATION
www.newport.com
843-R

1
Table of Contents
Chapter 1.Introduction: How to Use This Manual .3
Chapter 2.Quick Reference ................................4
2.1 Getting Started..............................................................4
2.2 Functions with no Sensor Connected .......................5
2.3 Thermal Sensors...........................................................7
2.4 Photodiode Sensors................................................... 10
Chapter 3.The 843-R Power Meter Unit .............12
3.1 General Description ...................................................12
3.2 Smart Connectors ......................................................13
3.3 Soft Keys......................................................................14
3.4 Power Up and Shut Down.........................................15
3.5 843-R Functions that are Independent of Sensor Type
.........................................................................................16
3.6 843-R Measurement Screens...............................19
3.7 Hardware Functions ..............................................21
Chapter 4.Operation with Thermopile Absorber
Sensors.........................................................24
4.1 Thermopile Absorber Sensors..................................24
4.2 Startup Configuration............................................25
4.3 Power Measurement.............................................25
4.4 Energy Measurement ............................................35
Chapter 5.Operation with Photodiode Sensors ...47
5.1 Photodiode Sensors .............................................. 47
5.2 Startup Configuration ............................................47
5.3 Power Measurement.............................................48

2
5.4 Special Cases of Power Measurement ..............60
Chapter 6.Circuit Description ...........................62
6.1 Analog Module.......................................................62
6.2 Processor Board:........................................................63
Chapter 7.843-R Power Meter Specifications.....64
7.1 System/Meter Specifications ...................................64
7.2 Thermal Sensor Specifications ................................64
7.3 Photodiode Sensor Specifications ..........................65
7.4 Warranty......................................................................65
7.5 Technical Support Contacts .....................................66

3
Chapter 1.
Introduction: How to Use This Manual
Newport’s 843-R Power Meter is a simple to use
microprocessor-based Laser Power/Energy meter that
operates with thermopile and photodiode sensors. Based
on smart connector technology, just connecting the
sensor configures and calibrates the instrument.
This manual tells you what you need to know to make full
use of the 843-R for all your laser measurement needs. It
includes a "Quick Reference", (Chapter 2) to allow you to
perform basic measurements immediately, without
reading the whole manual.
The main measurement sections, Chapters 4 and 5
include a general description and a section detailing
operating options.

4
Chapter 2.
Quick Reference
2.1 Getting Started
To connect a sensor to the 843-R Power Meter, simply
insert the 15 pin D type connector of the measuring
sensor cable into the socket marked "Sensor Input" on the
rear panel of the 843-R Power Meter (see Figure 2.1).
The 843-R Power Meter is equipped with "soft keys." That
is, the functions of the keys change as indicated by the
legend above each key (see Figure 2.2).
Figure 2.1 843-R Rear Panel
12VDC AN OUT SENSOR INPUT USB OTG

5
2.2 Functions with no Sensor Connected
2.2.1 Turning on and off.
To switch the 843-R Power Meter on:
Briefly press the on/off switch (Figure 2.2). The unit will
switch on, and the display will appear.
Figure 2.2 843-R Front View

6
Note:
With the 843-R Power Meter, sensors are hot
swappable. Even after the meter is switched on, you
can remove one sensor and insert a different one.
The 843-R will recognize the switch and reconfigure
itself according to the settings of the new sensor.
To toggle the state of the LCD backlight:
The backlight for the 843-R’s LCD can be toggled between
3 different levels of illumination. This toggling will be
performed by briefly pressing the on/off switch after the
843-R has been switched on.
To switch the 843-R off:
Press the on/off switch and hold it for about 2 seconds
until the display blanks.
2.2.2 Configuring the instrument.
To zero instrument:
1. Make sure that the instrument is not in an electrically
noisy environment and is undisturbed.
2. Verify that no sensor is connected. If one is
connected, then detach before continuing.
3. Press the Zero key. This will bring you to the Zeroing
screen
4. Press the Start key. When zeroing finishes
press the Save key.
To show or hide settings
1. Press the Down arrow until Show Settings is
highlighted and press the Enter arrow.
2. Set to Yes to display sensor settings in the
measurement screens. Set to No to hide the sensor
settings and show a larger graph.

7
To set Line Frequency
1. Setting Line Frequency correctly removes electrical
noise that may be introduced to the measurements.
2. Press the Down arrow until Line Frequency is
highlighted and press the Enter arrow.
3. Set to 50Hz or 60Hz, depending on the electrical
power grid of the area that you are in.
To set Date and Time
1. Press the Down arrow until the Date and Time are
highlighted and press the Enter arrow.
2. Scroll through and select Month, Day, Year, Hour,
and Minutes with the Right arrow. Change the
selected item with the Down arrow.
Note:
The present settings are automatically saved for the
next time the 843-R is turned on.
2.2.3 Updating the 843-R Firmware.
1. Download the latest 843-R firmware upgrade
package from the Newport website:
http://www.newport.com and copy to your target
directory.
2. Run the upgrade executable and follow the on
screen instructions
2.3 Thermal Sensors
2.3.1 Use of the 843-R with thermal type sensors.
Most Thermopile sensors have somewhat different
absorption at different wavelengths. In order to
compensate for this, each sensor has been calibrated by
laser at several wavelengths. When you choose the

8
correct laser wavelength, the correction factor for that
wavelength is automatically introduced. Note that the
laser wavelength correction in use is displayed in the
upper left corner of the display.
To set type of laser being used:
1. From the measurement screen, press the Setup key.
2. Press the Down arrow until Laser is highlighted and
press the Enter arrow.
3. Select the appropriate laser wavelength and press
the OK key.
To select a range for power measurement:
1. From the measurement screen, press the Setup key.
2. Press the Down arrow until Range is highlighted and
press the Enter arrow.
3. Select the appropriate manual range or AUTO to
select autoranging and press the OK key.
To choose power or energy measurement:
1. In the main measurement screen, press the Mode
key.
2. Select Power or Energy.
3. Press the OK key to return to the measurement
screen
2.3.2 Other Settings and Saving the Startup Configuration
1. When measuring power, you can set the period over
which to Average the measurements
2. When measuring energy you can set the threshold
level in order to screen out false triggers.
3. The present settings are automatically saved for the
next time the 843-R is turned on.

9
2.3.3 Power or Single Shot Energy Measurement
Warning:
Do not exceed maximum sensor limits for power,
energy, power density and energy density as listed in
Error! Reference source not found. and Table 6 in
Chapter 7. Otherwise, there is a risk of damaging the
absorber.
To simulate an analog needle display on the 843-R:
1. Press the Display key and select Needle.
2. Press OK to continue with measurements.
To expand the graph (Bargraph or Needle) scale ±5x
about the present reading:
1. Press the Zoom key.
2. Press the Zoom key again to return to the full scale
graph. See Section 4.3.1.2 for full details.
To subtract background and set current reading to zero:
1. Press the Offset key.
2. Press the Offset key again to cancel. See Section
4.3.1.2 for full details.
To use the 843-R to measure laser power:
1. Press the Mode key and select Power
2. Select AUTO for autoranging or the lowest manual
range whose maximum is greater than the expected
power readings.
3. Power is measured 15 times per second.

10
To use the 843-R to measure laser energy:
1. Press the Mode key and select Energy
2. Energy measurement is performed in manual ranges
only. The correct range to select is the lowest one
that is larger than the expected pulse energy to be
measured.
3. Thermal sensors measure energy in single shot
mode. When the 843-R flashes "READY," on and off,
fire the laser.
2.4 Photodiode Sensors
2.4.1 Selecting Wavelengths
1. From the measurement screen, press the Setup key.
2. Press the Down arrow until Laser is highlighted and
press the Enter arrow.
3. Select the appropriate laser wavelength and press
the OK key.
4. If the wavelength you want is not among the
wavelengths in the six wavelengths listed press the
Modify key.
5. Use the Right and Down arrows to adjust the
wavelength as desired. Then press the OK key.
2.4.2 To select a range for power measurement:
1. From the measurement screen, press the Setup key.
2. Press the Down arrow until Range is highlighted and
press the Enter arrow.
3. Select the appropriate manual range, AUTO to select
autoranging, or dBm to display power in a
logarithmic scale. Press the OK key
2.4.3 Other Settings and Saving the Startup Configuration
1. Select Average in order to set the period over which
to average the measurements

11
2. Select Filter to IN or OUT according to if the Filter is
in place or not.
3. The present settings are automatically saved for the
next time the 843-R is turned on.
2.4.4 Power Measurement
Warning:
Do not exceed maximum sensor limits for power,
energy, power density and energy density as listed in
Table 6 in Chapter 7. Sensor Specifications.
Otherwise, there is a risk of damaging the sensor.
To simulate an analog needle display on the 843-R:
1. Press the Display key and select Needle.
2. Press OK to continue with measurements.
To expand the graph (Bargraph or Needle) scale ±5x
about the present reading:
1. Press the Zoom key.
2. Press the Zoom key again to return to the full scale
graph. See Section 5.3.1.2 for full details.
To subtract background and set current reading to zero:
1. Press the Offset key.
2. Press the Offset key again to cancel. See Section
5.3.1.2 for full details.

12
Chapter 3.
The 843-R Power Meter Unit
3.1 General Description
The model 843-R laser power/energy meter represents a
new level of sophistication, sensitivity, compactness and
accuracy, coupled with ease of operation. It can operate
with thermal and photodiode sensors. It has smart
connector technology. Simply plugging in the sensor
configures and calibrates the 843-R to operate with that
sensor.
The 843-R’s large size TFT 320x240 screen enhances
measurement readouts in ways that smaller displays
cannot.
The 843-R displays power measurements in both digital
and analog form at the same time and also has a needle
type display. It can be set to autorange, so you do not
have to set scales; or to a manual range if you wish. It will
remember what mode you were using before you turned it
off and will return to that mode when turned on. You can
zoom in on the present reading, or subtract background.
The 843-R reads the calibration information that is stored
in the sensor’s smart connector and is ready to measure
from the moment it’s powered up. You can also zero the
843-R at the touch of a button.
The 843-R’s user interface is self-explanatory; you should
not have to refer to this manual very often. Above all, the
843-R has advanced circuitry and digital signal
processing for excellent sensitivity, signal to noise ratio,
accuracy, and response time. It also has special circuitry
to reject electromagnetic interference.
The 843-R has all the infrastructure for field upgrading of
the embedded software, should the need arise.

13
3.2 Smart Connectors
The 843-R meter is versatile and can operate with either
thermal or photodiode type laser measuring sensors. The
sensor configuration and calibration information is stored
in an EEROM in the sensor connector plug. This means
that when the sensor is plugged in, the 843-R
automatically identifies the sensor type, calibration and
configuration. The user does not have to adjust anything.
Figure 3.1 843-R displaying power measured with a Thermopile
sensor. Displayed in analog needle mode with persistence on.

14
Note:
With the 843-R, sensors are hot swappable. Even
after the meter is switched on, you can remove one
sensor and insert a different one. The 843-R will
recognize the switch and reconfigure itself according
to the settings of the new sensor.
When no sensor is plugged in, the 843-R meter gives the
user the opportunity to hide or show settings, change the
line frequency setting, and set the real time clock. It also
shows the serial number of the instrument, last
calibration date and firmware version. The user can also
re-zero the instrument. See section 3.5.
3.3 Soft Keys
The soft keys have functions defined by the legend above
the key. The legend usually indicates what will happen
when pressing the key. For example, if "Mode" appears
above a key, pressing that key will open a menu to allow
user to select between Power and Energy measurement
modes. Some functions operate when the key is pressed
and are canceled when the key is pressed again. Those
keys show reverse highlighting when operational.
Pressing the same key again cancels the operation and
the highlighting.
Key Functions
The 843-R has certain conventions as to the meaning of
standard key strokes and these are as follows:
Highlighted item: The highlighted item is the item that is
presently active.
OK: Returns to the previous screen with the selected
setting for immediate use and saved for next startup.

15
Cancel: Cancels the selection and returns to the previous
screen, leaving the settings unchanged.
Start: This puts into operation the active item.
Exit: This gets you to the previous screen and saves
changes made until instrument is turned off.
Save: This saves changes permanently. The change is
implemented now and is also saved for future use of the
instrument.
3.4 Power Up and Shut Down
To turn the 843-R on:
Briefly press the On/Off Switch.
The unit will switch on, and the display will appear. If no
sensor is connected, the Setup screen will appear. If a
sensor is connected, the appropriate default
measurement screen will appear.
To toggle the state of the backlight on and off:
The backlight for the 843-R’s LCD can be configured to
toggle between low, half, and full intensity (see Section
3.7.1 for full details). This toggling will be performed by
briefly pressing the On/Off switch after the 843-R has
been switched on.
To switch the 843-R off:
Press the On/Off switch and hold it for about 2 seconds
until the display blanks.
The current measurement settings will be saved
automatically for the next time the 843-R is powered up.

16
3.5 843-R Functions that are Independent of Sensor
Type
When no sensor is connected, the 843-R setup screen
will be displayed. This gives the user the opportunity to
hide or show settings, change the line frequency setting,
and set the real time clock. It also shows the firmware
version, serial number of the instrument, and last
calibration date. The user can also re-zero the
instrument.
3.5.1 Show or Hide Settings
1. Press the Down arrow ( ) until Show Settings is
highlighted and press the Enter arrow ( ).
2. Set to Yes to display sensor settings in the
measurement screens. Set to No to hide the sensor
settings and show a larger graph.
3. Press the OK key to keep the new setting.
Figure 3.2 843-R Setup Screen with no sensor connected.

17
3.5.2 Line Frequency
1. Setting Line Frequency correctly removes electrical
noise that may be introduced to the measurements
2. Press the Down arrow ( ) until Line Frequency is
highlighted and press the Enter arrow ( ).
3. Set to 50Hz or 60Hz, depending on the electrical
power grid of the area that you are in.
4. Press the OK key to keep the new setting.
Note:
The present settings are automatically saved for the
next time the 843-R Power Meter is turned on.
3.5.3 Analog Output
The 843-R Power Meter has an analog output with a full-
scale output of 1 Volt.
For thermal and photodiode sensors in power mode, the
analog output is continually updated 15 times per second
with the latest power measurement. For thermal sensors
in single shot energy mode, the analog output is held
fixed until the next pulse triggers.
3.5.4 Clock Settings
The 843-R Power Meter is equipped with a real time clock
which will show the date and time. This clock will also
allow the 843-R Power Meter to query the sensor
attached and notify you if the sensor is due for
calibration.
To set Date and Time
1. Press the Down arrow ( ) until the Date and Time
are highlighted and press the Enter arrow ( ).
2. Scroll through and select Month, Day, Year, Hour,
and Minutes with the Right arrow ( ). Change the
selected item with the Down arrow ( ).

18
3. When finished, press the OK key to keep the new
setting.
3.5.5 Zero Adjustments
In 843-R Power Meter, all adjustments, including zeroing
internal circuits, are done from the software. This
ensures simple and accurate realignment. It is
recommended to re-zero the 843-R Power Meter every 2
months for best performance. The simple zeroing
procedure follows.
To zero instrument:
1. If a sensor is connected, disconnect it.
2. Press the Zero key to enter the Zeroing screen
3. Make sure that the instrument is not in an
electrically noisy environment and is undisturbed
4. Press the Start key and wait for message, "Zeroing
completed successfully".
5. Press the Save key to save the new zero settings.
6. Press the Exit key to return to the Setup screen.
Note (for Thermal Sensors only)
For best results with thermal sensors, it may be
necessary to do the procedure once with the sensor
disconnected and a second time with it reconnected.
After completing steps 1 - 6 above, Connect the sensor
and make sure it is at room temperature and well
shielded from any stray thermal power. It may be best
advised to lay the sensor with the absorber face down on
the table.
7. Connect the thermopile sensor. Ensure that is at
room temperature and well shielded from any stray
thermal power. It may be best advised to lay the
sensor with the absorber face down on the table.
Press the Zero key to enter the Zeroing screen
8. Press the Start key and wait for message, "Zeroing
completed successfully".
9. Press the Save key to save the new zero settings.
10. Press the Exit key to return to the Setup screen.

19
3.6 843-R Measurement Screens
3.6.1. Bargraph
The Bargraph is a ruler-like display in which the graph is
filled proportionally to the reading’s being a percentage
of full scale. The Bargraph display is available when
measuring power or energy.
Press the Zoom key to zoom in on a smaller section of the
range when readings are fluctuating slightly.
If you notice that noise has gotten into the measurement,
you can press the Offset key to remove it from the
measurement.
3.6.2. Needle
A Needle graph simulates an analog display, similar to
the style of an analog voltmeter or a car’s speedometer.
The Needle display is available when measuring power or
energy.
Press the Zoom key to zoom in on a smaller section of the
range when readings are fluctuating slightly.
Figure 3.3 Bargraph with Thermopile Sensor.