Program Example 4: IBM PC,Microsoft Basic, via GPIB

This program requires the Capital Equipment Corporation GPIB card for the IBM PC or XT. It has firmware in ROM to interface high level languages to the GPIB.

Subroutine calls in Microsoft BASIC are done to memory locations specified by the name of the subroutine. The address is relative to the segment address specified by the DEF SEG statement preceding CALL.

In this program, the CEC card's ROM starts at OC0000H, the system controller's address is 21, and the SR530 has been assigned as GPIB address 23.

To monitor the GPIB activity with an RS232 terminal, SW1-6 should be down, and the ASCII terminal should be attached to the rear panel RS232 connector.

10 ′ EXAMPLE PROGRAM TO READ THE SR530 OUTPUT AND RAMP THE X6 ANALOG OUTPUT 20 ′ USING IBM PC BASICA AND THE CAPITAL EQUIPMENT CORP. GPIB INTERFACE CARD

30

40 ′ THE RAMP ON X6 CAN BE MATCHED BY SETTING THE SR530 DISPLAY TO D/A.

50

60 ′ ON THE SR530 REAR PANEL, SET SWITCHES #4 AND #6 ON SW1 TO DOWN (DEVICE 70 ′ ADDRESS = 23, RS232 ECHO ON) AND SWITCH # 1 ON SW2 TO DOWN (RS232 BAUD 80 ′ RATE = 9600). ALL OTHER SWITCHES SHOULD BE UP.

90 ′ NOTE THAT THE RS232 ECHO IS FOR DEBUGGING AND DEMOSTRATION PURPOSES,

100 ′ UNDER NORMAL CONDITIONING, SWITCH # 6 OF SW1 SHOULD BE UP SINCE THE RS232 110 ′ ECHO SLOWS DOWN THE GPIB INTERFACE.

120

130

DEF SEG = &HC000

′BASE ADDRESS OF CEC

CARD

140

INIT=0: TRANSMIT=3:

RECV=6: ′ADDRESSES OF CEC FIRM WARE ROUTINES

150

ADDR%=21: SYS%=0

′CONTROLLER

ADDRESS

160INZ$ = ″IFC UNT UNL MTA LISTEN 23 DATA ′Z′ 13″

170

180Q1$ = ″IFC MTA LISTEN 23 DATA ′Q1′ 13″

190Q2$ = ″IFC MTA LISTEN 23 DATA ′Q2′ 13″

200X6$ = ″IFC MTA LISTEN 23 DATA ′X6, ″

210LISN$ = ″IFC UNT UNL MLA TALK 23″

220

230

240

CALL

INIT(ADDR%,SYS%)

′INIT X6 OUTPUT

TO ZERO

250

CALL

TRANSMIT(INZ$,STATUS%)

′RESET

SR530

STATUS

260

GOSUB 600

′CHECK

TRANSMIT

270

280 X = 0 ′INIT X6 OUTPUT TO ZERO

290

300

CALL

TRANSMIT(Q1$,STATUS%)

′READ CHANNEL 1 OUTPUT

310

GOSUB 600

′GET RESULT

320

GOSUB 510

330

V1 =

VAL(ANS$)

′INTO V1

340

350

CALL

TRANSMIT(Q2$,STATUS%)

′READ CHANNEL 2 OUTPUT

360

GOSUB 600

′GET RESULT

370

GOSUB 510

380

V1 =

VAL(ANS$)

′INTO V2

51

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SRS Labs SR530, Lock-In Amplifier manual Program Example 4 IBM PC,Microsoft Basic, via Gpib

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.