Introduction 
Chapter 1 
1-1 
1.1 How to Use This Manual 
This manual gives detailed instructions for setting up and operating the 
SIGNAL RECOVERY Model 7230 DSP Lock-in Amplifier. It is split into the 
following chapters:- 
Chapter 1 - Introduction 
Provides an introduction to the manual, briefly describes the function of a lock-in 
amplifier and the types of measurements it may be used for, and lists the major 
specifications of the model 7230. 
Chapter 2 - Installation and Initial Checks 
Describes how to install the instrument and gives a simple test procedure which may 
be used to check that the unit has arrived in full working order. 
Chapter 3 - Technical Description 
Provides an outline description of the design of the instrument and discusses the 
effect of the various controls. A good understanding of the design will enable the 
user to get the best possible performance from the unit. 
Chapter 4 - Front and Rear Panels 
Describes the instrument’s connectors and indicator as referred to in the subsequent 
chapters. 
Chapter 5 - Web Control Panel Operation 
Describes the capabilities of the instrument when operated via the built-in web 
control panels. 
Chapter 6 - Computer Operation 
This chapter provides detailed information on operating the instrument from a 
computer via the built-in interfaces. It includes information on how to establish 
communications, the functions available, the command syntax and a detailed 
command listing. 
Appendix A 
Gives the detailed specifications of the unit. 
Appendix B 
Details the pinouts of the multi-way connectors on the rear panel of the unit. 
Appendix C 
Shows the connection diagrams for suitable RS232 null-modem cables to couple the 
unit to a compatible computer. 
Appendix D 
Provides a listing of the instrument settings produced by using the Auto-Default 
functions. 
Appendix E 
Gives an alphabetical listing of the computer commands for easy reference. 
New users are recommended to unpack the instrument and carry out the procedure in 
chapter 2 to check that it is working satisfactorily. They should then make 
themselves familiar with the information in chapters 3, 4 and 5, even if they intend 
that the unit will eventually be used under computer control. Only when they are