DH Instruments PPCH-G, Руководство по эксплуатации и обслуживанию

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4. REMOTE OPERATION
Page 87 © 2007 DH Instruments, a Fluke Company
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4.1 OVERVIEW
Most of the PPCH-G front panel functions can also be executed by commands from a remote computer.
The host computer can communicate to the PPCH-G using the PPCH-G COM1 RS232 port or the
IEEE-488 port.
Before writing test code, which makes use of PPCH-G remote commands, familiarize yourself with its
operating principles by reading Section 3 of this manual.
4.2 INTERFACING
Sending a program message to the PPCH-G places it into
remote
mode. The remote indicator to the
right of the display window lights when the PPCH-G is in
remote
mode. It will also flicker when a
program message is received. The menus usually accessed from the front panel are locked out while in
remote. The
[ESC]
key returns the PPCH-G to local operation unless the
<REMOTE>
program
message, which locks out all keypad operation, was sent to the unit. Going from remote to local or from
local to remote aborts any active generation.
4.2.1 RS232 INTERFACE
4.2.1.1 COM1
The PPCH-G COM1 RS232 interface is located on the back of the unit. It is a 9-
pin male DB-9F connector configured as a DCE device. Data is transmitted out
of the unit using pin 2, and is received on pin 3. This allows a normal pin-to-pin
DB-9M to DB-9F RS232 cable to be used to connect to a DTE host.
Handshaking is not required or supported. The COM1 receive buffer is
80 bytes deep. If you overflow the buffer by sending too much data, the data will
be lost. Because of this, you
must
send a single program message at a time
and you
must
wait for the PPCH-G to reply from the previous command before
issuing another command.
Table 15.
COM1 pin designations and connections
PPCH-G COM1 DB-9F PIN DESIGNATIONS
PIN # FUNCTION DESCRIPTION
2 TxD This pin transmits serial data from the PPCH-G to the host.
3 RxD This pin accepts serial data from the host computer.
5 Grn This pin is the common return for the TxD and RxD signals.
IBM PC/XT DB-9F
CONNECTIONS
IBM PC/XT DB-9M TO PPCH-G DB9F
CONNECTION
DB-25M DB-9F DB-9M DB-9F
2 3 3 3
3 2 2 2
7 5 5 5