Keithley 263 User Manual

IEEE-488 PROGRAMMING
4.7.9 M (SRQ Mask and Serial Poll Byte Format)
Purpose
Format
Parameters
Default
Description
Program which conditions will generate an SRQ (service request).
Mn
MO SRQ disabled
M2 Charge done
Ml6 Ready
M32 Error
Upon power up, or after the instrument receives a DCL or SDC command, SRQ
is disabled (MO).
SRQ Mask--The Model 263 uses an internal mask to determine which conditions
will cause an SRQ to be generated. Figure 4-7 shows the general format of this mask,
which is made up of eight bits. The Model 263 can be programmed to generate an
SRQ under one or more of the following conditions:
1. When a charge is done (M2).
2. When the instrument is ready to accept bus commands (M16).
3. When an error condition occurs (M32).
Serial Poll Byte Format--The serial poll byte contains information relating to data
and error conditions within the instrument. The general format of the status byte
(which is obtained by using the serial polling sequence, as described in paragraph
4.6.7) is shown in Figure 4-7. Note that the various bits correspond to the bits in
the SRQ mask as described above.
The bits in the serial poll byte have the following meanings:
Bit 0 Not used; always set to zero.
Bit 1 (Charge Done) - Set when not sourcing charge. Cleared (0) while sourcing
charge.
Bit 2 Not used; always set to zero.
Bit 3 Not used; always set to zero.
Bit 4 (Ready) Set when the instrument has processed all previously received com-
mands and is ready to accept additional commands over the bus. Cleared upon
receipt of “X’.
Bit 5 (Error) - Set when one of the following errors have occurred:
1. An illegal device-dependent command (IDDC) or an illegal device-dependent com-
mand option (IDDCO) was transmitted.
2. The instrument was programmed when not in remote.
3. A number error has occurred.
4. A self-test error has occurred.
This bit is cleared when the Ul status word is read to determine the type of error
(see paragraph 4.7.12).
Bit 6 - Set if the Model 263 asserted SRQ. Cleared when the instrument is serial
polled.
Bit 7 Not Used; always set to zero.
4-19

Keithley 263 Specifications

General

Brand	Keithley
Model	263
Category	Test Equipment
Language	English