Rohde & Schwarz R&S FSP Series, Operating Manual

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Operating Manual 1164.4556.12 - 06 8.9
R&S FSP Maintenance and Instrument Interfaces
Instrument Interfaces
8.3.3.4 Control Characters
For interface control, several strings are defined and control characters are reserved
which are based upon GPIB control.
8.3.3.5 Handshake
Software handshake
In the software handshake mode of operation, the data transfer is controlled using
the two control characters XON / XOFF.
The instrument uses the control character XON to indicate that it is ready to receive
data. If the receive buffer is full, it sends the XOFF character via the interface to the
controller. The controller then interrupts the data output until it receives another XON
from the instrument. The controller indicates to the instrument that it is ready to
receive data in the same way.
Cable required for software handshake
The connection of the instrument with a controller for software handshake is made
by crossing the data lines. The following wiring diagram applies to a controller with a
9-pin or 25-pin configuration.
Fig. 8.5 Wiring of the data lines for software handshake
Control string or character Function
'@REM' Switch over to remote
'@LOC' Switch over to local
'@SRQ' Service Request SRQ (SRQ is sent by the instrument)
'@GET' Group Execute Trigger (GET)
'@DCL' Reset instrument (Device Clear DCL)
<Ctrl Q> 11 Hex Enables character output / XON
<Ctrl S> 13 Hex Inhibits character output / XOFF
0D Hex, 0A Hex Terminator <CR>, <LF>
Controller
25-pin
Instrument
9-pin
1
2
3
4
5
6
7
8
9
Controlller
9-pin Instrument
9-pin
1
2
3
4
5
6
7
8
9 1
3
2
6
5
4
8
7
9
8
2
3
6
7
20
5
4
22
RxD / TxD
TxD / RxD
GND / GND
RxD / TxD
TxD / RxD
GND / GND