6
Änderungen vorbehalten
F u n c t i o n s a n d s e t t i n g s
6. Functions and settings
6.1 Flow control (SH1, AH1)
The fl ow control is for both transmitter and receiver (SH – Sour-
ce Handshake / AH – Acceptor Handshake) is required for all
further functions incl. the transmission of bus specifi c control
data and therefore supported. Extended fl ow control with the
possibility of a simplifi ed indication is not implemented.
6.2 Transmission and reception of data (T6, L4)
The instrument is able to transmit and receive data if the cor-
responding function (T – Talker / L – Listener) has been activated
by the control device. For addressing of both functions the same
primary basic address has to be used. Secondary addresses
are not supported.
“Talk Only” and “Listen Only” modes cannot be activated.
6.3 State information (SR1, PP1)
Interface state information can be polled in sequential mode
(Serial Poll) as well as simultaneously from several devices
(PP – Parallel Poll) from the bus. All required interface set-
tings for parallel polling are made by the control device via the
IEEE488-Bus.
If the confi guration of the device enable register is applicable
(note SCPI programming commands) the interface indicates the
control device internal state changes (SR – Service Request).
This avoids waiting time for the instrument’s reply or the recur-
rent query for the instrument state. The required device settings
must be made each time the device is switched on.
6.4 Communication initialisation (DC1)
Bus specific control commands “DCL” (Device Clear) and
„SDC“ (Selected Device Clear) will be processed by the internal
management, independent of other SCPI commands still to be
processed (DC – Device Clear). Within the instrument the SCPI
command processing will be newly initiated, the execution of
current commands will be interrupted, and the data buffer will
be deleted. The fl ow control cannot indicate the acceptance for
new data transmission until these data have been completely
processed.
6.5 Not supported functions (RL0, DT0, C0, CF0)
The following functions are not supported:
Switch over between local and remote with the opportunity to
lock local controls (RL – Remote Local)
External start of the instruments basic functions (DT – Device
Trigger)
Bus controller operation (C – Controller)
Considering the control device IEEE-488 bus cable length (CF
– Confi guration)
Local controls can be locked by SCPI commands (note SCPI
programming commands).
6.6 Bus driver (E1)
The IEEE-488 bus data and control lines are controlled by dri-
vers with open collector outputs. As to be seen in IEEE-488.1
standard, this enables a data rate of up to 250000 Bytes per
second.
6.7 Addressing of IEEE-488 devices
The IEEE-488 standard specifi es the address structure for
transmitter and receiver functions of a device. It allows you to
assign separate addresses for different device functions such
as transmission and receiving functions or for several different
transmission and receiving functions as appropriate.
These addresses can consist of a primary and a secondary part.
Both have a variable part (5 bit) for the real address and a fi xed
group allocation (2 bit). The 8th bit is not used.
Thus instrument addresses in the range from 0 to 30 (00h to
1Eh) are available. The address 31 (1Fh) has a special function.
It is used to deactivate the function of an addressed group on
the bus (UNL – Unlisten / UNT – Untalk).
The following address groups are specifi ed:
Primary addresses for receiver function (coding: 20h)
Primary addresses for transmitter function (coding: 40h)
Secondary addresses (coding: 60h).
E.g. the complete primary address of the receiver function of a
device with the basic address 8 will be 40 (28h).
6.8 Selection of Primary Address
The selection of an address is only possible if, as described
under item 4 (Oscilloscope Firmware) a fi rmware version
05.105-yy.yyy or higher is present in the scope and the interface
HO740 is fi tted.
Pressing the SETTINGS pushbutton calls the “Settings” menu.
The function key “Interface” opens the submenu “Settings
Interface” causing “IEEE-488” and highlight “Address x” to be
displayed. The address (x) can be changed between 0 and 30 by
turning the INTENS knob. Please note that the selected address
must not used by any other instrument on the bus.
