19
When the unit is active (on line) it will operate
in an echo back mode so that data sent from
the terminal will be transmitted back for verifi-
cation. When the unit is "on line", use the
proper serial transmit commands to request
data or set a new value. Be sure to send only
one command at a time followed by a carriage
return to insure proper operation. If an error
is made, a correction can be made by back
spacing and retyping correct data before the
return (enter) is sent. Once a return (enter) is
sent, the unit begins processing the data and
will transmit the requested data on a non-
priority basis over the data transmit line. The
unit will not transmit data if the Printer Busy line
is activated (high). When the Printer Busy line
is activated all transmissions are halted until
the line goes low or open. There should be a
pause after data is requested to insure that all
data has been transmitted before making an-
other request or addressing another unit. If
transmission has not started within two sec-
onds after data is requested, it can be as-
sumed that there is a problem. The unit
transmits a carriage return and line feed after
each data value. The unit will stay "on line"
until another unit is addressed.
RS232/RS422 - PC INTERFACE:
The following BASIC program is for setting up
RS232/RS422 on serial port (#1) at 300 baud.
Run this program after connecting the serial
interface connections.
10 SCREEN 0,0:WIDTH 80
20 CLS:CLOSE
30 OPEN "COM1:300,n,8,1,CS,DS,CD" AS #1
40 ON ERROR GOTO 110
50 B$=INKEY$
60 IF B$< >"" THEN PRINT #1,B$;
70 IF EOF (1) THEN 50
80 A$=INPUT$ (LOC(1),#1)
90 PRINT A$;
100 GOTO 50
110 RESUME
SO XXXXX: (set lock code)- Sets lock code at
requested value.
EO: (examine code)- Unit will transmit present
code (i.e. o=000XXXXX).
SF X: (set rate decimal location)- Sets rate decimal
at requested location (0 to 4).
EF: (examine rate decimal location)- Unit will trans-
mit the present rate decimal location
(i.e. f = 0000000X).
G XXXXXX: (lock unit)- Locks and unlocks unit.
(XXXXX = code)
SQ X: (set totalizer decimal location)- Sets total-
izer decimal at requested location (0 to 4)
EQ: (examine totalizer decimal location)- Unit will
transmit present total decimal location (i.e.
Q = 0000000X).
SU XXXX: (set totalizer scale factor)- Sets totalizer
scale factor at requested value. This factor
divides the totalizer by 1, 10, 100 or 1000.
(i.e. SUXXX100 sets the divider at 100
where "X" represents the required space
characters.
EU: (examine totalizer scale factor )- Unit will
transmit present total scale factor (i.e. U =
XXX100 where "X" represents the space
characters).
L CRPVABLH: (list)- The list can consist of any
combination of the eight available options.
Any address with a "*" next to it can be
listed.
SERIAL INTERFACE OPERATION:
Data is received and transmitted over stan-
dard EIA RS232 or RS422 levels. Each ten bit
character is made up of a start bit, eight bit
ASCII code and a stop bit.
The input impedance of RS232 is 3K
Ω
to 7K
Ω
worst case. The terminal addressing the unit
must be capable of driving all loads in the loop.
The input impedance of RS422 is much higher
and there should be no problem driving as
many as 99 units. The transmit line remains in
a high impedance "off" state until addressed.
Only one unit is to be on line at a time!!! More
than one unit on line could damage the unit or
destroy the transmitted data.
Содержание INT-69R
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