Tektronix 494AP service manual ADDRinstrumentbusaddresscommand

Thesecommandsand queriesare transmittedto the !ryl*rn Anatyzer with ihe pRtNT st#ment. rne upecrrumAnatyzerresp-onseto a query is input into a stringvariablewith the tNpUTstatement.A string vari- ableis-formeclpVendinOth€ variablenamewith a doilar sign($),€.9. A$, Xt$.

FOr thE GPIB PRIMARY ADDRESS,ENtEr tIiE

equivalentof the spectrr, '.'--'

9"_g'g"lrear-panel GPIBADDRESSswitchsettings. "n"lyi"r

Malntenance- 4g4N494ApServiceVol. 1

ADDR(instrumentbusaddress)command

HEX DIGIT - A character in the sequence0 through9 and A throughF that representsa hexade_ cimal digit. The two digits (in ordei; torm a numberto representa locationon the instrumentbus usedby fot_ lowing DATA commands. lf a characteris not a hexa- decimaldigit or part of a pair of digits,it is not usedto €xecutethe ADDRcommand,andan error is reported.

ADDR (instrument bus address) query

B.419 chip selectoutputs from U1044and Uptton switchenablelineson the Memory board.

4416-92A

Figure6-39. Insfument bus check.

Responseto ADDRquery

r_----{-a

DATA(instrumentbus data) command

HEXDIGITS- As with ADDR,a pairof digitsforms

ahexadecimalnumber.The numberis a data valueto b€ sent on the instrumentbus to the locationspecified by the last ADDR command.This allows internalspec- trum analyzerparametersto be set for service:these parameterscontrol functions by setting the status or modeof spectrumanalyzercircuitassembliesUp. to .16 pairs of charactersare accepted.lf a characteris not a hexadecimaldigit or part of a pair of digits, the data byte formedby the pair is not executedand an error is reported.Also, an error is reportedwhendatais sentto an invalidaddress.

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