Fluke A70M User Manual

Page of 148
 
4. REMOTE OPERATION 
 
Page 73 
© 2007 DH Instruments, a Fluke Company 
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4.1 
OVERVIEW 
Most of the RPM4 front panel functions can also be executed by commands from a remote computer.  
The host computer can communicate to the RPM4 using the RPM4’s COM1 RS232 port or it’s IEEE-488 port. 
Before writing code using RPM4 remote commands, familiarize yourself with its operating principles by 
reviewing Section 3 of this manual. 
4.2 
INTERFACING 
Sending a program message to the RPM4 places it into remote mode.  The remote indicator to the right 
of the display window lights when the RPM4 is in remote mode.  It also flickers 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 RPM4 to local operation unless the <REMOTE> program message, which locks out all 
keypad operation, was sent to the unit. 
4.2.1 
RS232 INTERFACE 
4.2.1.1 
COM1 
The RPM4 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 RPM4 to reply from the previous command before 
issuing another command. 
Table 12.  COM1 pin designations and connections 
RPM4 COM1 DB-9F PIN DESIGNATIONS 
PIN # 
FUNCTION 
DESCRIPTION 
TxD 
This pin transmits serial data from the RPM4 to the host. 
RxD 
This pin accepts serial data from the host computer. 
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 RPM4 DB9F 
CONNECTION 
DB-25M 
DB-9F 
DB-9M 
DB-9F 
3 2 2 2