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3-23
Sending Data Words
3-30
Before a data word is sent, a command must be
issued establishing the controller as the ''talker'' and the
59501B as the''listener''. The following examples assume
that the controller (9825A calculator) has been assigned it stan¬
dard talk and listen addresses of "U" and "5" respectively, and
the 59501B has been assigned a listen address of
3-31
Example 1 illustrates a command statement issued
by a 9825A calculator. Note that in addition to the
calculator talk address "U" and the 59501B listen address
the address code of the HP-IB Interface Card
(98034A) must be included. It is assumed that the interface
card has been assigned its standard select code of "7".
The 9825A command statement also includes a constant
data value of "1250" which is sent to the 59501B.
Example 1. Sending a Constant Data Value
(9825A Command Satement)
59501B Listen Address-
Calculator Talk Address
Uniisten Command-
98034A Select Code
1
cmd 7, "?U&"
Range Digit
Magnitude Digits
'1250"
Data Word
3-32
Example 2 illustrates a write statement (9825A
calculator) which can also be used to address the 59501B
to listen and send a constant data value. The 59501B- listen
address of
corresponds to an address of "06" as defined
in the 9825A General I/O ROM manual (09825-90024)
Chapter 4. Note the format statement (line 0) used in
Example 3. The "c" specifies a character field, while the -
"z" is used to suppress carriage return/line feed codes at the
end of the write statement. Suppression of the carriage
return/line feed codes is essential when programming the
59501B . If they are not suppressed, they will be processed
as data characters by 59501B resulting in an undesired
output.
Example 2. Sending a Constant Data Value
(9825A Write Statement)
-Suppresses CR/LF Codes
0: fmt 1, c, z
1: wrt 706.1, "1250"
98034A Select
Code
59501B Address
3-33
Command statements can only be used to send
data constants. Write (9825A) statements can be used to
send data constants but must be used to send variables.
3-34
Example 3 illustrates how a write statement (9825A)
is used to send variable data to the 59501B . If variable N in
line 1 were equal to 1250, this example would program the
same output as the previous examples. Format specification
f4.0 deletes leading spaces and the z suppresses the CR/LF
codes for the same reasons as described above.
Example 3, Sending Variable Data
(9825A Write Statement)
0: fmt 1, f4.0, z
1: wrt 706.1, N
3-35
USING 59501B AS A POWER SUPPLY
PROGRAMMER
3-36
Power supply programming is accomplished using
the digitally controlled output voltage of the 59501B in
conjunction with the ZERO ADJUST and POWER SUPPLY
FULL SCALE ADJUST controls on the 59501B front panel.
By making the appropriate connections between the
59501 B's output terminals and the voltage programming
terminals of a dc power supply, the output voltage (or cur¬
rent) of the power supply can be programmed from zero to
the full rated output. This method of programming is
called voltage programming with gain.
3-37
Voltage Programming With Gain
3-38
HP programmable power supplies have certain
features in common. These features include: an internal
reference (either a fixed regulated voltage or a fixed regu¬
lated constant current source), voltage and current compara¬
tors with their input terminals, and front panel controls
(voltage and current) with connections at the rear panei
terminals. A power supply can be controlled by making
the appropriate connections on the rear panel and applying
an external voltage (or in some cases current). For example,
by disconnecting the internal reference voltage from the
input circuits of the constant voltage comparator and
replacing it with an external voltage source, the output
voltage of the power supply is programmed by the value of
the external voltage source.
3-4
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