3. GENERAL OPERATION
Page 119
© 1998-2008 DH Instruments, a Fluke Company
PRINCIPLE
PG7000 has three RS232 communications ports referred to as COM1, COM2 and COM3
and a single IEEE-488 port. COM1 and the IEEE-488 port are for communicating with a host
computer (see Section 4). COM2 is for communicating with an external barometer and/or
vacuum gauge (see Section 3.11.5.4, 3.11.5.5) or for pass through commands to an RS232
device. COM3 is reserved for communications with an automated pressure
generation/control component and/or an AMH automated mass handler (see Section 3.9.9).
The communication ports can be set up from the PG7000 front panel.
PG7000 provides a self-test for its RS232 communication ports. The self-test allows
verification that the PG7000 RS232 ports (COM1, COM2, COM3) are operating properly and
that a valid interface cable is being used. (see Section 3.11.5.3)
OPERATION
To access the port communications settings, press
[SPECIAL]
and select
<5remote>
.
Select
<1COM1>
,
<2COM2>
,
<3COM3>
or
<4IEEE-488>
to view and edit that port’s
communications settings (see Section 4.2.1 for information on COM port settings). Selecting
<2COM2>
includes the choice to set up external barometer communications as well as the
port’s communications settings. Select
<1settings>
to view and edit COM2 communications
settings. Select
<2baro>
to view and edit external barometer communications settings (see
Section 3.11.5.4).
To access the RS232 self-test press
[SPECIAL]
,
<5remote>
,
<5RS232test>
.
3.11.5.1
COM1, COM2 AND COM3 (RS232)
The COMx ports can be set for the specific settings required by the user.
The settings are baud rate, parity, data bits and stop bits. The available options
are found in Table 21.
Table 21
.
COM1, COM2 and COM3 Available Settings
BAUD RATE
300, 600, 1 200, 2 400, 4 800, 9 600, 19 200
PARITY
NONE, ODD or EVEN
DATA BITS
7 or 8
STOP BITS
1 or 2
TERMINATORS
<CR><LF> or <LF><CR>
The default COMx settings are
2400, E, 7,1,
<CR><LF>
or
<LF><CR>
for all three
COM ports.
PG7000 appends a carriage return (
<CR>
) and a line feed (
<LF>
) or
<LF><CR>
to all messages that are sent out of the COM1 port to the host. It looks for a
carriage return to terminate incoming messages and ignores line feeds. The
user MUST wait for a reply to each message sent to PG7000 before sending
another message to it (see Section 4.3).
3.11.5.2
IEEE-488
The IEEE-488 port address can be defined from 1 to 31. The default address is
10
.
PG7000 sends a line feed (
<LF>
) and asserts the EOI line at the end of all
transmitted messages. It looks for a line feed and/or assertion of the EOI line to
terminate incoming messages.
