4. REMOTE OPERATION
Page 55 © 1998 DH Instruments, Inc.
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4.1 OVERVIEW
Most of the PPC2 AF front panel functions can also be executed by commands from a remote computer.
The host computer can communicate to the PPC2 AF using the PPC2 AF COM1 RS232 port.
4.2 INTERFACING
Sending a command to the PPC2 AF will place it into remote mode. The remote indicator in the lower left
hand corner of the PPC2 AF front panel will light when the PPC2 AF is in remote mode. It will also flicker
when a command is received. The menus usually accessed from the front panel will become locked out
while in remote. The ‘ESCAPE” key will return the PPC2 AF to local operation unless the “REMOTE”
command was sent to the unit, which locks out keypad operation.
Most remote commands will return a reply within 500 ms. You must wait for this reply before issuing
another command to the PPC2 AF. This insures that the PPC2 AF has completed the command. The following
commands take more than 500 ms to reply:
PR, PRR, SR, ATM, RATE Up to 2.0 seconds to allow a new measurement.
RESET Up to 12 seconds to reset the data and restart the PPC2 AF.
4.2.1 RS232 INTERFACE
The PPC2 AF 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.
4.2.1.1 COM1
PPC2 AF COM1 DB-9F PIN DESIGNATIONS
PIN # FUNCTION DESCRIPTION
2 TxD This pin transmits serial data from the PPC2 AF 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 PPC2 AF DB9F
CONNECTION
DB-25M DB-9F DB-9M DB-9F
2 3 3 3
3 2 2 2
7 5 5 5
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