Rockwell Automation 1771-DB BASIC MODULE - Manual (Page 306)

Chapter
Call Routines 69–127 13
13 -48
Use CALL 114 to transmit the DF1 data packet. When you perform
CALL 114, the DF1 data is posted for the DF1 driver to transmit as a
single message packet. If you selected half-duplex slave operation, the
message packet is transmitted the next time an ENQuiry is received from
the DF1 master. If you selected full-duplex operation, the message packet
is transmitted immediately.
Use one or more PRINT# (page11 -29), PH0.#, or PH1.# (page 11 -27)
statements to construct the desired data in the transmit buffer of port PRT2.
After constructing the data in the transmit buffer, use CALL 114 to initiate
transmission of the data inside a DF1 message packet.
Use caution when building DF1 data packets. If you attempt to transmit
five or less bytes of data (minimum is six bytes), the message
ERROR:
DF1 DATA PACKET TO TRANSMIT IS TOO SMALL is sent to the program
port and the BASIC module enters Command mode.
If you attempt to place more than 256 bytes of data into the transmit buffer,
the message
ERROR: BUFFER OVERFLOW is sent to the program port and
the BASIC module enters Command mode.
Your program must wait for one transmission to complete before
performing construction of another data packet. Use CALL 115 to check
the DF1 transmission status to determine when a transmission is complete.
Input and Output Arguments
This routine has no input or output arguments.
Syntax
CALL 114
Example
>1 REM EXAMPLE PROGRAM
>10 CALL 114
>20 END
CALL 114: Transmit DF1
Packet