Fluke 8845A - RS-232 Modes of Operation

8845A/8846A
Programmers Manual
8
RS-232 Modes of Operation
RS-232 communication is slightly different between the 8845A/46A and the Fluke 45
emulation modes. Switching between these two command languages is covered in the
“Selecting the Programming Language” section later in this manual. The following
sections explain the differences in communications protocol and how to set the Meter and
computer parameters for proper operation.
8845A/8846A Mode
There are two modes of RS-232 operation when the Meter has the 8845A or 8846A
command set selected:  and . The terminal mode is an
interactive mode where an operator inputs commands, with immediate returns for
requested information (queries) and interface messages. In terminal mode, characters sent
to the Meter are echoed on the host’s display screen and a command prompt (for example
3>) is returned after the CR/LF is entered by the terminal. If you send a character to the
Meter over the RS-232 interface, pressing the <DELETE> or <BACKSPACE> key
deletes the previous character. A backspace is echoed to the host terminal.
Note
^C (CNTRL C) is the RS-232 equivalent of IEEE-488 DCI (device clear),
causing “1>” followed by a carriage return and line feed to be output.
The computer mode is used when the Meter is operated by computer program. In this
mode, requested information is returned by query, and interface messages are queued and
returned by command. Characters are not echoed on the host computer and command
prompts are suppressed. The <DELETE> or <BACKSPACE> keys are ignored.
Selecting Between Computer and Terminal Mode
Although you can select between Computer and Terminal mode at any time, the selection
is only used or changed when the Meter’s command mode is set to 8845A/46A.
To select computer or terminal mode from the front panel:
1. Press  and then .
Note
If the RS-232 port is not already highlighted, press  and
then .
2. Press either ,  and select either  or
.
Fluke 45 Mode
In the Fluke 45 Command emulation mode, there are two modes of RS-232 operation:
 or . In Echo mode, characters sent to the Meter are echoed on the
host’s display screen. In No Echo mode, characters sent are not echoed.
To set the echo parameter, refer to the "Enabling and Disabling RS-232 Echo" section
earlier in this manual. If you send a character to the Meter over the RS-232 interface,
pressing the <DELETE> or <BACKSPACE> key deletes the previous character. A
backspace is echoed to the display screen if Echo On mode is set.
In either mode, when the host sends a command to the Meter over the RS-232 interface,
the Meter parses and executes the command, and returns a response if appropriate, and
sends one of three prompts: