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Annex
NRP2
362
User Manual 1173.9140.02 ─ 07
The IEC/IEEE 1174.1 mode
To allow emulation of the IEC/IEEE 488.1 standard, special control characters that
begin with an &
character (0x26) are defined (
). The link (link 1 or link 2) via
which the control sequences are to be transmitted and that (controller or measuring
instrument) is allowed to transmit the control sequences are predefined.
This means the following for communications via RS-232-C and Ethernet in mode
1174.1:
●
The special control sequences are permitted throughout the data stream. They are
recognized and filtered out by the driver. In particular, the control sequences are
also permitted within the block data and SCPI commands.
●
To distinguish between the & character of the control sequences and the normal &
character, the IEC/IEEE 1174.1 mode offers a double & mechanism: An & charac-
ter that does not initiate any control sequence is transmitted twice. The direction of
the transmission (device->controller, controller->device) is irrelevant. When
received, double && characters have to be split in half to yield single & characters.
●
The state changes "local
↔
remote" are achieved by receiving characters and by
means of the special control sequences.
Summary:
●
The state change from "local
→
remote" is achieved by receiving data and through
special control characters.
●
The state change from "remote
→
local" is achieved by clearing down the connec-
tion (peer sockets) and through special control characters.
●
Simultaneous operation of the measuring instrument via local in the remote state
can be achieved by using newly defined control characters (>M - GoTo Mixed).
The IEC/IEEE 1174.2 mode
The IEC/IEEE 1174.2 mode differs from the 1174.1 mode depending on where the
special control sequences are permitted in the data stream.
●
The special control sequences are only permitted outside block data and string
data.
●
The remote
→
local state changes are controlled by means of control sequences as
set forth in the IEC/IEEE 1174.1 mode. The state changes are triggered by the
reception of characters and by special control sequences.
Summary:
●
The state change from"local
→
remote" is achieved by receiving data and through
special control characters.
●
The state change from "remote
→
local" is achieved by clearing down the connec-
tion (peer sockets) and by special control characters.
●
Simultaneous operation of the measuring instrument via local in the remote mode
can be achieved by using newly defined control characters (>M).
●
There are no & characters outside of block data within SCPI commands. Doubling
of the & characters is therefore not necessary in this mode. In the 1174.1 and
1174.2 modes, the special control sequences have a different device-internal
Remote control interfaces
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