DH Instruments PPC4, Operation And Maintenance Manual

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PPC4™ OPERATION AND MAINTENANCE MANUAL
© 2009 DH Instruments, a Fluke Company Page 138
6.4.2.1 Using Command Type Commands
Note
Enhanced format commands DO NOT reply when using the
IEEE-488 interface unless a “?” is included in the command.
There will be no response from PPC4 to non-query (no “?”)
commands. Remote software can time-out waiting for a
response from PPC4. However, in RS232 communications,
there is always a response and the response MUST be read
prior to issuing another command.
The COMMAND type of program message executes a process and can
additionally send data to the PPC4 in the form of comma delimited arguments.
This data is usually a setting of some sort that is stored in the PPC4. 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:” appears to the left of the
required syntax in each program message description in Section 6.5.4 .
If you are using the IEEE-488 port, the Command type does not generate a reply
unless you place a query operator
“?” immediately after the command. You also may
send multiple program messages at once by separating each program message
with a semicolon. The commands are queued and executed in as received order
after the entire message stream has been received, so care in determining order
of execution is needed.
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.
Examples:
•
IEEE-488 enhanced mode command series using query operator:
“*CLS?” (Clear the error queue. Wait for reply.)
“UNIT? KPA” (Generates a reply. User must wait for reply before continuing.)
“MMODE? A” (Generates a reply. User must wait for reply before continuing.)
“PS? 100” (Generates a reply. User must wait for reply before continuing.)
•
IEEE-488 enhanced mode commands without query operator:
“*CLS” (Clear the error queue. No reply.)
“UNIT KPA” (No reply)
“MMODE A” (No reply)
“PS 100” (No reply)
“ERR?” (Wait for reply. User should use “ERR?” query following a
series of non query commands to check for errors that may
have occurred.)
•
IEEE-488 enhanced mode multiple commands without query operator:
“*CLS” (Clear the error queue. No reply)
“UNIT KPA;MMODE A;PS 100” (Three commands at once. No reply)
“ERR?” (Wait for reply. User should use “ERR?”
query following a series of non query
commands to check for errors that may
have occurred)
•
COM1 enhanced mode command:
“*CLS” or “*CLS?” (Clear the error queue. Wait for reply.)