THORLABS PDA200C User manual

Photodiode Amplifier
PDA200C
Operation Manual
2020

Copyright © 2020 Thorlabs
Version:
Date: 3.5 12-May-2020

Foreword
Contents 2
1 General Information 3
31.1 Ordering Codes and Accessories
2 Getting Started 4
42.1 Parts List 42.2 Preparation
3 Operating Instruction 5
53.1 Operating Elements 73.2 Operation 73.2.1 Connecting a Photodiode 73.2.2 Offset Adjustment 83.2.3 Calibration of the Power Display 83.2.4 Setting a BIAS Voltage 93.2.5 Analog Control Output 93.2.6 Disabling the Beeper
4 Maintenance and Service 10
104.1 Line Voltage Setting 114.2 Replacing Mains Fuses 124.3 Troubleshooting
5 Appendix 13
135.1 Technical Data 155.2 Safety 165.3 Environmental Conditions 175.4 Manufacturer Address 185.5 Declaration of Conformity 195.6 Warranty 195.7 Exclusion of Liability and Copyright 205.8 Thorlabs Worldwide Contacts and WEEE Policy

© 2020 Thorlabs
We aim to develop and produce the best solution for your application
in the field of optical measurement technique. To help us to live up to
your expectations and improve our products permanently we need
your ideas and suggestions. Therefore, please let us know about
possible criticism or ideas. We and our international partners are
looking forward to hearing from you.
Thorlabs GmbH
Warning
Sections marked by this symbol explain dangers that might result in
personal injury or death. Always read the associated information
carefully, before performing the indicated procedure.
Please read this advice carefully!
This manual also contains "NOTES" and "HINTS" written in this form.
Attention
Paragraphs preceded by this symbol explain hazards that could
damage the instrument and the connected equipment or may cause
loss of data.
Note
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© 2020 Thorlabs
1 General Information
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1 General Information
The Thorlabs PDA200C is a precise photodiode current amplifier compatible with all kinds of
photodiodes. After a calibration the PDA200C can be used as precise optical power meter.
Typical applications of the PDA200C are:
·simple operation of photodiodes (transimpedance amplifier)
·sensitive pico-Ampère meter
·low noise amplification of photodiode current
·simple optical power meter
The PDA200C is easy to operate via the operating elements on the front panel. The operating
parameters are shown on an illuminated 5-digit LED display. Either PD-current, optical power or
bias voltage can be displayed. The displayed parameter is chosen by up / down toggle switches
and indicated by LEDs. The units of the measurement for current and power ranges are indic-
ated by LEDs. The unit for bias voltage is V.
The offset of the input amplifier and of the photodiode can easily be adjusted using a 12-turn
potentiometer.
The bias voltage ranging from 0 V to+10 V (for polarity anode grounded) or from 0 V to -10 V
(for polarity cathode grounded) can be applied to the photodiode using the sliding switch on the
rear panel of the PDA200C. The voltage is set using a 12-turn potentiometer.
The displayed power values can be calibrated for a known power level by a potentiometer.
The Analog Out provides a DC voltage proportional to the photodiode current.
The installed mains filter and the transformer shielding provide a low ripple at the analog control
output.
If requested Thorlabs offers calibrated photodiodes as accessories.
Attention
Please find all safety information and warnings concerning this product in the chapter Safety
in the Appendix.
1.1 Ordering Codes and Accessories
Ordering code Short description
PDA200C Photodiode amplifier / optical power meter
Thorlabs offers a variety of photodiodes for different wavelengths and power ranges, which can
be used with the PDA200C.
Please visit our homepage http://www.thorlabs.com for further information.
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PDA200C
2 Getting Started
2.1 Parts List
Please inspect the shipping container for damage. Please do not cut through the cardboard.
You might need the box for storage or for returns. If the shipping container seems to be dam-
aged, keep it until you have inspected the contents and you have inspected the PDA200C
mechanically and electrically.
Verify that you have received the following items within the package:
1. 1 PDA200C
2. 1 grounding cable
3. 1 flat-bladed screwdriver 1.8 x0.5 mm
4. 1 power cord, connector according to ordering country
5. 1 Quick Reference
2.2 Preparation
Prior to operating a PDA200C controller, check if the set line voltage matches with your local
power supply and if the appropriate fuses are inserted. See sections Line Voltage Setting
and Replacing the Mains Fuses .
Connect the unit to the power line using the supplied cable. Turn the unit on by pressing the
line switch (F9) .
Via the connector jack of the chassis ground (R2) the external optical setup can be connected
to ground potential, if required. The required grounding cable is attached.
Note
Grounding is strongly recommended in order to avoid hum and noise interference to the photo-
diode input, particularly when measuring low photodiode current.
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3 Operating Instruction
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3 Operating Instruction
3.1 Operating Elements
Operating elements at front panel
F1 - 5-digit LED display
F2 LED "nA" Current display in nA
F3 LED "µA" Current display in µA
F4 LED "mA" Current display in mA
F5 LED "nW" Power display in nW
F6 LED "µW" Power display in µW
F7 LED "mW" Power display in mW
F8 LED "BIAS ON” Bias voltage switched on
F9 - Line switch (ON / OFF)
F10 SET Potentiometer for setting the bias voltage
F11 CAL Potentiometer for calibrating the power display "POPT"
F12 LED “BIAS” Display shows the bias voltage in volts
F13 LED "POPT" Display shows the optical power
F14 LED "IPD" Display shows the photodiode current
F15 Key "DOWN" Select the parameter to be displayed
F16 Key "UP" Select the parameter to be displayed
F17 Key Range ”Down” Select the measurement range (increasing the sensitivity)
F18 Key Range “Up” Select the measurement range (decreasing the sensitivity)
F19 OFFSET Potentiometer for PD input offset adjustment
F20 PD INPUT Photodiode input

© 2020 Thorlabs6
PDA200C
Operating elements at rear panel
R1 Monitor control output "ANALOG OUT", 0 … ±10V
R2 4 mm banana jack for grounding
R3 Selector switch for the photodiode bias voltage: CG (-) / OFF / AG (+)
R4 Serial number of the unit
R5 Indicator / switch for line voltage (included in fuse holder)
R6 Mains connector and fuse holder

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3 Operating Instruction
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3.2 Operation
Attention
Prior to switch on the PDA200C please check if the line voltage setting (see the indicated
voltage in the fuse holder's window R5 ) corresponds to your mains voltage! If the selected
voltage does not match, please set it correctly as described in section “Line Voltage Setting ”.
Push the line switch (F9) to turn the unit on.
After switching on the unit, the LED display (F1) and one of the LEDs, indicating the selected
measurement value (F12 ... F14), lights up. If no display is shown, please check the line voltage
setting and the mains fuses.
Using up and down keys (F15) and (F16) the desired parameter can be selected.
The PDA200C is immediately ready to use after turning on. The rated accuracy is reached,
however, after a warming-up time of approx. 10 minutes.
3.2.1 Connecting a Photodiode
Photodiodes with both polarities, i.e. cathode or anode grounded, can be used with the
PDA200C. If a photodiode with anode connected to ground is used, the display (F1) shows a
negative sign.
Attention
If the polarity of the photodiode is not known, first set the bias switch (R3) to zero to avoid dam-
age to the diode!
·Select photo current display "IPD" using up / down keys F15) and F16).
·Select the 10 mA current (range keys F17 and F18).
·Connect the photodiode to the input jack "PD INPUT" (F20).
·Select an appropriate current range to show the actual photodiode current with the best
resolution on the LED display.
3.2.2 Offset Adjustment
The Offset Adjustment allows to compensate the input offset of the current amplifier or - if re-
quired - to zero the dark current of the connected photodiode. Offset and/or dark current adjust-
ment is recommended to proceed after the PDA200C has warmed up.
Offset compensation:
·Do not connect a photodiode to the input jack "PD INPUT" (F20).
·Select display IPD (F15/ F16).
·Select the 10 mA current range (F17/ F18).
·Using the screwdriver coming with the PDA200C, turn the potentiometer "OFFSET" (F19)
in order to achieve a zero IPD current in the display.
It is not necessary to repeat the offset correction after the current measurement range was
changed.
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PDA200C
Zeroing the PD's dark current
Connect the photodiode to the input jack "PD INPUT" (F20) and make sure the PD is darkened
completely. It might be useful to ground the photodiode's housing using the supplied grounding
cable, connected to the GND jack R2 on the rear panel
·Select display IPD (F15/ F16).
·Select the required PD current range (F17/ F18).
·Using the screwdriver, turn the potentiometer "OFFSET" (F19) in order to achieve a zero
IPD current in the display.Aftewr th
Note
After changing the IPD current range, the dark current compensation must be carried out again!
3.2.3 Calibration of the Power Display
The PDA200C can be calibrated in order to display the optical power incident to the connected
photodiode. The responsivity of the of the photodiode must not exceed the range 0.05 to 2
A/W. If the connected PD has a responsivity exceeding this eange, please contact Thorlabs for
a solution.
·Connect the photodiode and turn the PDA200C on.
·Expose the photodiode to a well known optical power. Make sure that no additional optical
power enters the photodiode.
·Select display IPD (F15 / F16).
·Select an appropriate current range (F17 / F18) to show the actual photodiode current
with the best possible resolution.
·Select display POPT (F15 / F16).
·Use the screwdriver to adjust the potentiometer "CAL" (F11) in order to get the value of
the optical power POPT displayed equal to the known power level.
This calibration is valid for all current ranges of the PDA200C.
3.2.4 Setting a BIAS Voltage
The PDA200C provides the possibility to apply a reverse voltage of up to ±10 V (bias) to the
photodiode (photo-conductive mode).
·Set the bias switch (R3 ) to “OFF”
·Connect the photodiode and turn on the PDA200C
·Expose the photodiode to light.
·Select the current range (F17 / F18).
If the displayed value is positive (polarity cathode grounded), set the bias switch (R3) to " - CG".
The applied bias voltage is negative.
If the displayed value is negative (polarity anode grounded), set the bias switch (R3) to " + AG".
The applied bias voltage is positive.
·Select Display “Bias” (F15 / F16).
·The bias voltage is displayed in volts.
·Use the screwdriver to set the potentiometer "SET" (F10) to the desired value for the bias
voltage.
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