Remote-processing RPC-210 Manuel d'utilisateur télécharger pdf (Page 23)

SERIAL & SPI PORTS BASIC SECTION 4

Page 4-5

Line 20 sets up ON COM$ to interrupt on a < CR> and

branch to line 1000. Line 30 sets up this card' s address.

Line 1010 checks to see if the received message = this

card's address. If not, the subroutine ends. When there

is a match, further processing is performed.

USING RADIO MODEMS

Using radio modems in a network is similar to using RS-

485 in a network. The only real difference is the modem

connects to the RPC -210 through the RS-2 32 serial po rt.

Some radio modem s use the CTS line to control the

transmitter. Others may require a separate TTL line.

One control line to consider the RS-485 transmitter

enable. This line is available at W6-1. When you need

to transmit, this line will go high when transmitting then

shut off. Depending upon the characteristics of your

transmitter, you may need a “ warm up” time befor e it is

stable. In this case, you may need to use one of the lines

from J7 to turn the transmitter on and off.

When using the RPC-210 in battery situations, power to

the modem may be switched on and off the ‘E’ power

terminal on P1. When the RPC -210 is powered on,

power is available to the modem. You control the actual

transmitter through a separate line.

ACCESSING SERIAL BUFFERS

Access CO M0 and C OM1 buffers in one of three ways:

1. INPUT statement. This removes all characters in

the buffer up to the term inator cha racter and puts

them into a variable.

When using the INPUT statement, program

execution is suspended until a < cr> (Enter key) is

received. W hether this is a problem depends on

your particular application.

INPUT strips bit 7. This means ASCII characters

from 0 to 127 are received.

2. GET function. Characters ar e rem oved one at a

time as an ASCII value. A 0 is returned when the

buffer is empty. Use the C OM function to

determine if the buffer is empty or if a 0 is an

ASCII value.

If you don' t read the buffer and the buffer fills, all

subsequent characters are discarded. GET m ay be

used anywhere in the program.

3. COM$(n) retrieves all characters in the buffer,

including other control codes (except CR).

ACCESSING COM0 AND COM1

The port INPUT and GE T functions retrieve data using

the UIn command. UI0 routes inputs to C OM0 while

UI1 routes inputs to the COM1 port. PRINT outputs are

set by the UOn com mand. UO0 p rints out C OM0 while

UO1 outputs COM1. PRINT #1, is an alternative way

to print to COM 1.

The following show how UIn and UOn work.

100 UI0 Set to COM0

110 INPUT A Get data from COM0 port

520 UI1 Switch to COM1 port

530 INPUT B Get data from COM1 port

800 REM Print to COM0

810 PRINT "Temperature:",T

900 REM Print to COM1

910 PRINT #1, "Set pressure

at:",CA

Power up default is set to COM0.

DISABLING CONTROL-C

Program execution is terminated by entering a

< Cntl> < C> . To disable < Cntl> < C> so program

execution is not terminated, execute the following

statement:

DBY(38) = DBY(38) .OR. 1

1 2 ... 18 19 20 21 22 23 24 25 26 27 28 ... 59 60

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Remote-processing RPC-210 Manuel d'utilisateur Page 23

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