DH Instruments PPCK PLUS, Operation And Maintenance Manual

Page: 80 / 150

PPCK+™ Operation and Maintenance Manual
©2001 DH Instruments, Inc .
Page 72
4.3.2.1 ENHANCED PROGRAM MESSAGE USING THE COMMAND TYPE
The COMMAND type of program message executes a process and can additionally
send data to the PPCK+ in the form of comma delimited arguments. This data is
usually a setting of some sort that is stored in the PPCK+. If data is specified, it must
be preceded by at least one white space from the program message header and be
within the range and format described in the program message description.
The keyword “Command:” will appear to the left of the required syntax in each
program message description.
If you are using the IEEE-488 port, the Command type does not generate a reply so
you do not need to wait for a reply. You also may send multiple program messages
at once by separating each program message with a semicolon. The commands will
be queued and executed in as received order.
If you are using the RS232 port COM1, the Command type will always generate a
reply so you
must wait for a reply before issuing another program message.
Because of this, you can only send one Command program message at a time while
using the COM1 port.
4.3.2.2 ENHANCED PROGRAM MESSAGE USING THE QUERY TYPE
The Query type of program message just requests data from the PPCK+. You must
wait for a reply with a query. If you send any type of program message to the
PPCK+ after a Query before receiving a reply, the program message will be
discarded and an error will be generated. Errors are reporting using the IEEE Std.
488.2 status reporting model. A Query program message always ends with a
question mark. Most queries will return a reply within 200 ms except:
PR?, PRR?, SR?, ATM?, RATE? Up to 2.0 seconds to allow a new measurement.
The syntax for using a QUERY program message is listed next to the keyword
“Query:” in each program message summary in Section 4.4.4.