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5-9
SERIAL REMOTE
OPERATION
The ML2430A Series Power Meter can be operated remotely through the rear
panel serial connector (See Chapter 3, Connectors, for the location of the serial
connector). Whereas GPIB has restrictions on total cable length and cable length
between instruments, RS232 serial communication is not as limited. The GPIB
can also be prone to electrical interference and is not easily electrically isolated,
while RS232 can be isolated using optical couplers. Serial interface remote oper
-
ation can be useful if the testing is to be done in the presence of high electrical
fields and like environments.
While most standard serial cables will suffice, a 9-pin null-modem serial interface
cable is available from Anritsu as an optional accessory (part number B41323).
Note that the hardware handshake CTS and RTS lines are used to control the
flow of data in and out of the power meter and must be available in the cable as
hardware handshaking is always enabled. The DTR and DSR lines are con
-
nected together within the meter.
The ML2430A Series Power Meter serial connector pinouts are:
PIN SIGNAL
1
NOT USED
2
RX data
3
TX data
4
DTR handshake signal
5
signal ground
6
DSR handshake signal
7
RTS handshake signal
8
CTS handshake signal
9
NOT USED
The serial interface baud rate can be set using the System|Rear panel|RS232
menu selection or the RSBAUD command (page 6-67). Available baud rates are:
1200, 2400, 4800, 9600 (default), 19200, and 38400. Other parameters are pre
-
defined as: 8 bits, no parity and 1 stop bit and cannot be changed.
Commands are entered as with the GPIB interface, conforming to the command
format for the operation (emulation) mode selected. All GPIB commands are sup
-
ported. There are some additional commands, specific to the serial interface, that
are prefixed with an exclamation mark (!). In the emulation modes, when running
under GPIB, the measured data is always available when the meter has been ad
-
dressed to talk. In serial mode, the meter cannot be addressed to talk, but mea
-
surement data can still be obtained by using the GPIB trigger commands TR1
and TR2 in the HP 437 and HP 438 emulation modes, and T and I in the HP 436
emulation mode. All GPIB type commands and command strings should be ter
-
minated with a new line character (0A hex). The special serial mode commands
do NOT require a termination character.
ML2430A OM 5-5
PROCEDURES SERIAL REMOTE OPERATION
NOTE
Serial interface remote
operation is not avail
-
able when the
ML2430A Series
Power Meter is operat
-
ing from the internal
battery.