DH Instruments PPC2+, Manual

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PPC2+™ Operation and Maintenance Manual
©2001 DH Instruments, Inc.
Page 84
4.4.3 PROGRAM MESSAGE DESCRIPTION OVERVIEW
Each program message description is separated into the following sections:
Purpose A brief description of the programs message’s function.
Command This is the Enhanced program message syntax to send data to the PPC2+ or to
execute a PPC2+ function. The PPC2+ must be set to use the enhanced format
(see Section 4.3). It may be sent alone, or followed by at least one white space and
additional argument(s) to show that arguments can be passed. If there are multiple
arguments, then commas must separate them. If you are using the IEEE-488 port,
multiple Command type program messages can be sent in one message if you
separate them with a semicolon. There will be no reply from the PPC2+ using the
IEEE-488 port. If you are using the COM1 port, the PPC1 will reply and you must
wait for this reply. If this field is not listed in the program message description, then
the Command type is not supported when using the Enhanced format.
Query This is the Enhanced program message syntax to request data from the PPC2+.
The PPC2+ must be set to use the enhanced format (see Section 4.3.2). The
PPC2+ will always reply to a query. You must wait for this reply before issuing
another program message. If this field (Query) is not listed in the program message
description, then the Query type for the program message is not supported when
using the Enhanced format.
Classic This is the Classic program message syntax to send data to the PPC2+, to execute a
PPC2+ function, or to query for data. This type of command is not recommended for
new applications. The PPC2+ must be set to use the classic format (see Section
4.3). It may be followed by a ‘(=)’ and additional argument characters to show that
argument(s) can be passed. If there are multiple arguments, then commas must
separate them. The PPC2+ will always reply to a Classic program message. You
must wait for this reply before issuing another program message. If this field is not
listed in the program message description, then it is not supported when using the
classic format.
Arguments If the program message can be used to set data inside the PPC2+, then this section
will describe the arguments and their limits.
Default If the program message can be used to set data inside the PPC2+, then this line will
show (using the enhanced format) the default setting from the factory.
Remarks This field has the details and remarks about the command.
Example Examples are given for the enhanced and classic methods.
Enhanced: An example of the use of an enhanced method program message to be
sent to the PPC2+ is shown. The message sent to the PPC2+ appears after the
“Cmd sent:” label. If only a Query type exists, the “Query sent:” label is shown
instead. Directly under this label, “Query reply” shows a typical reply to a query type.
“Reply:” shows that a query format does not exist. It may have a short description
next to it.
Classic: An example of the use of a classic program message to be sent to the
PPC2+ is shown. The command sent to the PPC2+ appears after the “Cmd sent:”
label. The “Reply” label shows a typical reply to the “Sent” example. It may have a
short description next to it.
Errors If the program message can report an argument error, the types of errors are listed.
If using the classic format or the COM1 port, the error message will be replied after
receiving the program message. If using the enhanced format via the IEEE-488 port,
the error condition will be handled by the status reporting model which will store the
errors in an Error Queue and can be programmed to assert the IEEE-488 SRQ line
to signal an error has occurred. In either case, the “ERR” or “ERR?” program
message can be used to retrieve a text description of the error.
See Also Indicates related program messages (“----“) and refers to manual sections giving
detail on PPC2+ operation corresponding to the program message.