The RS423 and GPIB Ports. Remote Control 1250 Frequency Response Analyzer
13-30 AMK/1250/4
13.15 FILE OUTPUT
A description of the File is given in Chapter 12, Section 2, which includes the
procedures for operating from the Front Panel. The File can also be controlled by
external Commands via the RS423 and GPIB ports, but readings can only be placed in
the File by the 1250 itself, not from outside.
Remote control of the File is achieved by using a combination of Commands from
Section 13.7.13 "File Commands" and 13.7.15 "Data Output Commands". By using the
appropriate Command, any of the relevant DATA OUTPUT key facilities are available,
for example the readings can be transferred via either port in Dump mode, as described
in Section 13.12.4. Also, new Limits can be applied to the readings as they are read
from the File, by using the Function Commands given in Section 13.7.17.
Before storing data in a new File, it is advisable to send an FC (Clear File) Command.
The 1250 must be placed in ANALYZER STOP mode, before the File is read.
Unlike remote control of the Learnt Program, no Device Control characters are
generated when using the RS423 port.
13.15.1 PROCEDURE TO OUTPUT THE FILE VIA RS423 PORT, BY
EXTERNAL COMMAND
1. Ensure that the 1250 is in LOCAL 1 or LOCAL 2 mode.
2. Set up the relevant external device, connected to the RS423 port.
3. Instruct the 1250 to switch the RS423 section of the DATA OUTPUT switch to "all" by
sending the Command:
OP 1,1
from the external device.
4. Instruct the 1250 to list the File by sending the Command:
FO
from the external device.
5. The contents of the File will now be copied to the external device via the RS423 port.
13.15.2 PROCEDURE TO OUTPUT THE FILE VIA GPIB PORT
There are two methods of transferring the contents of the File to an external device via
the GPIB port, depending upon the rate at which the Controller can handle data.
a. Fast Method. The 1250 transmits the File contents at the rate of approximately one
reading every 40 milliseconds (12 milliseconds in Dump Mode). Provided that the
Controller rate is faster than this, the 1250 merely has to "list" the File at its
maximum speed. A typical Controller program for this method is shown in Section
13.15.3.
b. Slower Method. This method includes a "handshake" routine to ensure that no data
is lost. A typical Controller program is shown in Section 13.15.4.
Both examples use the Controller program statements defined in Section 13.8.
For any mode other than Dump, the readings will be transferred from the File in the
form shown in Section 13.12.3, including the Separators and Terminator, which can
be selected as described. In the Controller program examples given, it is assumed
that the Separator is "comma”.
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