SRS Labs Lock-In Amplifier manual SR530 Guide to Operation Rear Panel

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SR530 Guide to Operation Rear Panel

AC Power

The ac line voltage selector card, line fuse, and line cord receptacle are located in the fuse holder at the left side of the rear panel. See the section, Preparation for Use at the front of this manual for instructions on setting the ac voltage selector and choosing the correct fuse.

GPIB Connector

The SR530 has an IEEE 488 (GPIB) interface built in. The GPIB address is set using SW1 located to the right of the interface connectors. Refer to page 7 for switch setting details.

RS232 Connector

The SR530 has an RS232 interface. The connector is configured as a DCE. The baud rate, parity, stop bits, and echo mode are selected using SW2 located to the right of the interface connectors. Refer to Page 7 for switch setting details.

Signal Monitor Output

This BNC provides the buffered output of the signal amplifiers and filters. This is the signal just before the demodulator. The output impedance is <1Ω . When a full scale input is applied, the peak- to-peak amplitude at this output is 20 mV, 200 mV or 2 V for dynamic reserve settings of high, norm, and low, respectively.

Preamp Connector

This 9 pin "D" connector provides power and control signals to external peripherals such as pre- amplifiers. The available power is described below.

Pin

Voltage

Current Available

1

+20

100 mA

2

+5

10 mA

6

-20

100 mA

7Signal ground

8Digital ground

General Purpose A/D and D/A

There are four analog input ports, labeled X1 through X4. These inputs may be digitized and read via the computer interfaces. The range is -

10.24V to +10.24 V and the resolution is 2.5 mV. The input impedance is 1 MΩ . A digitization can be performed in about 3 mS but the result may take longer to transmit over the interface being used.

There are two analog output ports, labeled X5 and X6. The voltages at these ports may be programmed via the computer interfaces. The range is -10.24 V to +10.24 V and the resolution is

2.5mV. The output impedance is <1Ω and the output current is limited to 20 mA.

Ratio

Output X5 is the ratio output when not programmed by the computer interface or set via the front panel. X5 becomes the ratio output whenever the unit is turned on.

The voltage at X5 is the ratio of the Channel 1 Output to the analog voltage at port X1. An output of 10 V corresponds to a ratio of 1. The ratio is computed by digitizing the Channel 1 Output and the voltage at port X1 and then taking the ratio. The resolution is 2.5 mV. For best accuracy, the sensitivity should be set to provide at least a 50% full scale signal and the analog denominator (X1) should be 5V or greater. The ratio is updated approximately every 3 mS. For the Ratio feature to work, the voltage at the denominator input must exceed 40 mV.

When the DISPLAY is set to D/A, the ratio output is 10 times the magnitude, R, divided by X1.

Internal Oscillator

The INTERNAL OSCILLATOR is a voltage controlled oscillator with a sine wave output . To use the oscillator as the reference source, connect

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Contents Model SR530 Page Table of Contents Appendix C Gpib NON-OPERATING OperatingPage SR530 Specification Summary Gpib DemodulatorFront Panel Summary Enbw Abridged Command List Status Byte Definition Configuration SwitchesSignal Filters Signal InputsSR510 Guide to Operation Front Panel SensitivityStatus Dynamic ReserveDisplay Select Channel 1 DisplayOutput Channel OutputRel Channel Offset ChannelExpand Channel Rcosø OutputChannel 2 Display Auto Phase Rsinø Output Reference InputTrigger Level Phase Controls Reference ModeReference Display Time ConstantPower DefaultsLocal and Remote SR530 Guide to Operation Rear Panel Page SR530 Guide to Programming Command SyntaxCommunicating with the SR530 Front Panel Status LEDsTry-Out with an Ascii Terminal RS232 Echo and No Echo OperationLOW Norm High SR530 Command ListN1,n2,n3,n4 Page Errors Status ByteBit Trouble-Shooting Interface Problems ResetCommon Hardware Problems include Common Software Problems includeSR530 with the Gpib Interface SR530 with the RS232 InterfaceSerial Polls and Service Requests Gpib with RS232 Echo ModeSR530 with Both Interfaces Measurement Example Lock-in TechniqueShielding and Ground Loops Understanding the SpecificationsPage Page SR530 Block Diagram Phase Sensitive Detectors Signal ChannelReference Channel DC Amplifiers and System GainCircuit Description Demodulator and Low Pass Amplifier Reference OscillatorExpand Analog Output and ControlFront Panel Microprocessor ControlPower Supplies RS232 InterfaceGpib Interface Multiplier Adjustments Amplifier and Filter AdjustmentsCalibration and Repair Replacing the Front-End Transistors Notch FiltersNon-Essential Noise Sources Appendix a Noise Sources and CuresPage Page Appendix B Introduction to the RS232 Case 1 The Simplest ConfigurationBaud Rate Case 2 RS232 with Control LinesParity Stop BitsVoltage Levels Final TipBus Description Appendix C Introduction to the GpibProgram Example IBM PC, Basic, via RS232 Appendix D Program ExamplesProgram Example IBM PC, Microsoft Fortran v3.3, via RS232 Page #include stdio.h Program Example IBM PC, Microsoft C v3.0, via RS232Page Program Example 4 IBM PC,Microsoft Basic, via Gpib ′INCREMENT X6 Output by 2.5 MV Program Example HP85 via Gpib Documentation PC1 Oscillator Board Parts ListSW1 DpdtBR1 Main Board Parts ListBR2 BT1SR530 Component Parts List SR530 Component Parts List PIN D 22U MINGpib Shielded CX1CY1 FU1MPSA18 SR530 Component Parts List SR530 Component Parts List SR530 Component Parts List SR530 Component Parts List SR530 Component Parts List SPSTX8 4PDTSR513 Assy SR530 Component Parts List Static RAM, I.C Z80A-CPUTranscover TIE AnchorMica #4 FlatFront Panel Board Parts List RED LD1 LD2LD3 Quad Board Parts List SR530 Component Parts List PC1 SR530 Component Parts List Miscellaneous Parts List SR530 Component Parts List

SR530, Lock-In Amplifier specifications

The SRS Labs Lock-In Amplifier, model SR530, is a powerful tool designed for high-precision measurements in the realm of scientific research and industrial applications. This state-of-the-art instrument excels in extracting small signals from noisy environments, making it an invaluable asset for experiments in fields such as physics, engineering, and materials science.

One of the main features of the SR530 is its ability to perform synchronous detection, which is key to improving signal-to-noise ratios. By utilizing a reference signal, the device correlates the incoming signal with the reference to effectively filter out noise, allowing for the accurate measurement of weak signals that might otherwise be obscured. This process of phase-sensitive detection is fundamental to the operation of the Lock-In Amplifier.

The SR530 offers a wide frequency range, covering from 0.1 Hz to 100 kHz. This broad frequency response allows it to handle a diverse array of signals, making it suitable for various applications including optical detection, capacitance measurements, and in many cases, voltammetry. The device is also equipped with multiple inputs and outputs, facilitating the integration with other laboratory equipment and enabling complex experimental setups.

Precision is further enhanced with its adjustable time constant, which allows users to optimize the response time based on experimental needs. The user can choose time constants from 10 microseconds to 10 seconds, accommodating fast dynamic measurements as well as those requiring stability over longer durations.

Another remarkable characteristic of the SR530 is its digital processing capabilities. The device features a highly accurate digital voltage measurement system, minimizing drift and ensuring long-term stability. Additionally, the use of microprocessors enhances data handling and allows for features such as programmable settings, facilitating automated measurements.

Moreover, the SR530 includes a range of output options, including analog outputs, which can be used for direct signal processing, as well as digital interfaces for integration with computers. This ensures that users can not only capture high-fidelity data but also analyze and display it efficiently.

In conclusion, the SRS Labs SR530 Lock-In Amplifier stands out due to its sophisticated technology, versatile features, and robust performance. Its precision, flexibility, and ease of use make it an ideal choice for researchers and engineers looking to unlock the potential of weak signal measurement in complex environments.
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