HP 3335A - HP-IB Programming and Control; HP-IB Bus Commands and Programming; Special Attenuator and Programming Sequence

Section IH
b. By pulling the IFC (interface Clear) line low. This
asynchronously clears all instruments on the bus.
c. By giving the “GO TO LOCAL” command (GTL,
001 Octal, ASCII “SOH”).
d. By turning the instrument off.
3-80. HP-IB Bus Commands. The Bus Commands are
divided into three categories:
a. Unaddress Commands (UNL and UNT)
b. Universal Commands (LLO, DCL, SPE, ete.)
c. Addressed Commands (SDC, GTL, GET, etc.)
The 3335A will not respond to all of the bus commands. Its
operation is unaffected by a command it does not recog-
nize. The commands it will respond to are UNL (Unlisten),
LLO (Local Lockout), DCL (Device Clear), SDC (Selective
Device Clear) and GTL (Go To Local). Each of these com-
mands is listed above following its respective command
category.
3-81. PROGRAMMING.
3-82. Programming of the 3335A functions is by means of
data messages sent by the system controller over the HP-IB.
Table 3-5. Programming Codes.
ASCII Octa! Decimal | Hexadecimal
KEY Character | Code Code Code
83 53
STORE S 123
RECALL R 122 82 52
FREQUENCY F 106 70 46
FREQ INCR l 111 73 49
AMPLITUDE A 101 | 65 41
AMPTD INCR l 111 73 49
G INCR | p 120 80 50
SWEEP WIOTH | w 127 87 57
DISPLAY LAST | L 114 76 4c
ENTRY ;
o o 060 48 | 30
1 1 061 49 | 31
2 2 062 s0 | 32
3 3 063 51 33 i
4 4 | 064 52 34 |
5 5 | 065 53 35 |
6 6 066 54 36
7 7 067 55 37
8 8 070 56 | 38
9 3 071 57 i 39
056 46 2E
BACK SPACE B 102 66 42 |.
CLEAR C 103 | 67 | 8
MHz/—dBm M 115 | 7 | 40
kHz/+dBm K 113 75 4B
Hz/deg H 1100 | 72 48
INCR Î U 125 85 55
INCR 4 D | 104 68 44
GOTO START | 6 i 107 71 47
FREQ ;
START 10 SEC x 130 88 58
SINGLE
START 50 SEC | Y 131 89 59
SINGLE
START AUTO z 132 90 5A
STOP Q 121 31 51
sg 055 45 | 2D
**See Paragraph 3-81 T 124 84 54
3-14
Model 3335A
These messages are composed of two parts — the address
command and the program information. The address com-
mand contains the “talk” and “listen” addresses of the
devices involved, here the controller talk address and the
3335A listen address. The program information contains
the codes of the 3335A keys to be programmed. Syntax of
the address command portion of the data message is
dependent on the controller used (see manual of the system
controller). Syntax for the program information portion is
comprised of the program codes listed in Table 3-5.
3-83. Each programming code is a single 7-bit word or
“byte”, Table 3-5 lists each front panel key that is program-
mable and lists the programming code by ASCII character
and corresponding octal, decimal and hexidecimal equiva-
lant. The last two entries of the table (— and T) are codes
programmable but do not represent front panel keys. The
“_” allows for ease in programming amplitudes since nega-
tive amplitudes can be preceded by the minus sign and all
amplitudes finalized with the + dBm key (K) from the
HP--IB. The character T is discussed in the following para-
graph.
3-84. A special operating condition is obtainable by using
the programming code ASCII character “T”. This HP-IB
command sets the attenuator to the straight-through posi-
tion and the impedance to the 50 ohm mode. A change of
amplitude cannot be programmed but the digits 1 through
7 will introduce the attenuator pad corresponding to the
“AT” line associated with the programmed digit (ie.,
programming the digit 4 causes the AT4 line to go low and
introduce the 10 dB pad associated with line AT4). Pro-
gramming a O sets the attenuator straight through again
once a pad has been introduced. The digit 8 programs the
50 ohm output while the digit 9 programs the 75 ohm out-
put. To return to normal amplitude control, the code C
(CLEAR) must be programmed to exit the special operating
condition. A summary of the “T” special operating codes
and their function is shown in Table 3-6,
3-85. The 3335A will respond to programming codes only
when it is addressed to listen in the remote mode. Front
panel key instructions can be entered in any order desired
by the programmer. The function key instruction must pre-
face a data entry for that function. An entry instruction
must follow the data to complete programming of the func-
tion changing that particular operating parameter. The key
instruction sequence of a program is identical to the key
activation sequence when operated manually. Examples of
program data messages using a 9830A and 9825A calculator
3-86. Examples illustrating complete programs using a
9830A and 9825A calculator to program various para-
meters and functions of the 3335A are shown in Figure 3-4.
3-87. Programming the Increment Functions. Special
attention to the programming of the amplitude, frequency
and phase increment functions is required because the same
instruction (ASCH character I) for increment is used. The
increment parameter programmed depends on the instru-
ment’s operating function prior to the “I” instruction. If