KEPCO TMA VXI-27 - Manual (Page 25)

3-8
TMA VXI -27 101602
3.4.1 TYPICAL VXIBUS START-UP SEQUENCE
The following is a typical sequence of commands which are sent to the TMA VXI-27 by the
resource manager upon power up:
1. The first command is READ PROTOCOL; the TMA VXI-27 replies with 8623 Hex (as
described in Table 3-2 above).
2. the next command is READ INTERRUPTERS to determine the IRQ line assigned to the
TMA VXI-27 interrupter.
3. This is followed by ASSIGN INTERRUPTER LINE which connects the TMA VXI-27 inter-
rupter to an active IRQ line (between 1 and 7) if the resource manager wants events sent as
interrupts. This can be followed by READ INTERRUPTER LINE if the resource manager
wants to verify that the interrupter is connected to the requested IRQ line.
4. After configuration commands described above, it is expected that the resource manager will
issue the BEGIN NORMAL OPERATION COMMAND followed by *idn? (SCPI command) to
identify the TMA VXI-27.
5. The power modules connected to the TMA VXI-27 can now be programmed using either
SCPI (PAR. 3.5) or CILL (PAR. 3.6) commands sent as Word Serial Protocol Messages.
3.5 SCPI PROGRAMMING
SCPI (Standard Commands for Programmable Instruments) is a programming language con-
forming to the protocols and standards established by IEEE 488.2 (reference document ANSI/
IEEE Std 488.2, IEEE Standard Codes, Formats, Protocols, and Common Commands). SCPI com-
mands are sent to the TMA VXI-27 controller as output strings within the selected programming
language (PASCAL, BASIC, etc.) in accordance with the VXIbus command protocol (PAR. 3.4).
3.5.1 SCPI MESSAGES
There are two kinds of SCPI messages: program messages from controller to power supply,
and response messages from the power supply to the controller. Program messages consist of
one or more properly formatted commands/queries and instruct the power supply to perform an
READ PROTOCOL
ERROR Issued by the COMMANDER to interrogate the TMA VXI-27 about the
cause of its current error (the TMA VXI-27 has activated the Err bit in
the Response register). The errors which can be reported by the TMA
VXI-27 are the following: Multiple Queries, Unsupported Command,
DIR Violation, DOR Violation, Write Ready Violation.
YES NO
READ STB Used to read the status word from the TMA VXI-27. Because the TMA
VXI-27 is a class I4 Instrument (implementing the IEEE 488.2 com-
mon commands), the value returned is the same as the value read by
executing *STB?.
NO YES
NOTE: It is more advantageous to execute the VXIbus Word Serial Protocol READ STB command than the *STB? because it is
faster (only one VXI cycle) and more accurate than *STB? It is more accurate because STB? is a query (which asks for
Word Serial Read; BYTE REQUEST command is the reply) which will always have the Message Available bit reset
(because taking the reply empties the output queue). Instead, the VXI READ STB shows the exact status of the output
queue (it does not use the output queue for the reply).
TABLE 3-2. VXI BUS COMMANDS (CONTINUED)
VXI Command Description
TMA VXI-27
Responds if active
substate is:
Configure
Normal
Operation