Front Panel Aspects Of Ieee-488 Operation; Buserrors; Numbererrors; Basic Statements Necessary To Send Bus Commands - Keithley 263 Instruction Manual

IEEE-488 PROGRAMMING
Table 4-2. BASIC Statements Necessary to Send
Bus Commands
Action
Transmit string to device 08.
Obtain string from device 08.
Send GTL to device 08.
Send SDC to device 08.
Send DCL to all devices.
Send Remote Enable.
Cancel Remote Enable.
Serial poll device 08.
Send Local Lockout.
Send IFC
HP-65 Statement
4.5 FRONT PANEL ASPECTS OF IEEE-488
OPERATION
The Model 263 has a number of front panel messages
associated with IEEE-488 programming. These messages,
which are listed in Table 4-3, are intended to inform you
of certain conditions that occur when sending device-
dependent commands to the instrument. The following
paragraphs describe the front panel error messages
associated with IEEE-488 programming.
Another front panel aspect of bus operation is local lockout
(LLO). Front panel controls are functional unless the LLO
command was asserted. See paragraph 4.6.3 for more in-
formation on LLO.
I'
Table 4-3. IEEE-488 Front Panel Messages
bErr
nElT
out
star
Bus error, no remote, IDDC or IDDCO.
Number error. Invalid value command
(A, L or V).
Flashing exponent decimal point(s) indi-
cate that calibration constants were
changed but not stored (temporary cali-
bration). Also flags an NVRAM error on
power up.
Calibration switch in disable position.
Permanent storage of calibration constant
(in NVRAM) not performed.
Permanent storage (in NVRAM) of cal
constants performed. Calibration switch
in enable position.
4.5.1
Bus
Errors
A bus error will occur if the instrument receives a device-
dependent command when it is not in remote, or if an
illegal device-dependent command (IDDC) or illegal
device-dependent cornman d option (IDDCO) is sent to the
instrument. Under these conditions, the complete corn-
mand string will be rejected and the following message
will be displayed:
bErr
In addition, the error bit in the serialpoll byte (paragraph
4.7.9) and pertinent bits in the Ul word will be set
(paragraph 4.7.12). The instrument can be programmed
to generate an SRQ under these conditions.
A no remote error can occur when a command is sent to
the instrument when the REN line is false. Note that the
state of REN is only tested when the X character is re-
ceived. An IDDC error can occur when an invalid com-
mand such as ElX is transmitted (this command is invalid
because the instrument has no command associated with
that letter). Similarly, an IDDCO error occurs when an ir-
valid option is sent with a valid command. For example,
the command F9X has an invalid command because the
instrument has no such command option.
HP-85 Programming Example-To demonstrate a bus er-
ror, send an IDDC with the following statements:
OUTPUT 708;"ElX"
When the statement is executed, the bus error message
appears on the display for about one second.
4.5.2 Number Errors
A front panel error message is used to flag a number er-
ror. A number error occurs when an out of range calibra-
tion value (A or L) or output value (V) is sent over the
bus. A number error also occurs if the V command is sent
while in the OHMS function. A number error will cause
the value command to be ignored. However, other com-
mands in the command sequence will be executed. The
following message is displayed briefly when a number er-
ror occurs:
nEl.r
The instrument can be programmed to generate an SRQ
4-5