5.
COMMANDS
Commands are given
in
ASCII-coded form. There are two types of commands:
1.
Commands for the total System
21
that have
to
be routed to the master unit.
2.
Commands for individual units that must be routed
to
the specific unit.
A
full survey of these command codes can be found
in
the annex (for master
commands and
slave commands valid for all slaves) and in the operating cards of
the
individual units (for specific unit dependent commands).
Examples:
Message Description
"AID;RESET" is a message to the master (AID) with the command
(RESET) to reset the system to the power-on conditions.
"AI 0201 ;CLOSE2,0PEN4"
is
a message to the slave PM2120 with address setting 1
(AID201) with the commands
to
close switch 2 and
to
open switch 4.
6.
READING
DATA
FROM
SYSTEM
21
To
input data from System
21,
first a command message requesting for this data has
to be sent and after that the system has
to
be addressed
as
talker to read the data.
Example:
6
on P2000C on HP85
100
IEC
PRINT
#11,"AID311;1NP
H"
100
OUTPUT
711;"AID311;1NP
H"
110
IEC INPUT #11,R$
110
ENTER
711;R$
The first message is a request to the
PM2131
with address switch set to 1
to
send
the data, which is
on
the input lines. With the second statement the data are read
from the system.
Note: An input statement always returns the result
of
the last request for data.
Earlier sent requests are automatically cancelled.
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