Omron CQM1H-SCB41 Example Programs, Using the TXD-- Instruction, Example Program for

Connections Section 4-4

Using the TXD(––) Instruction

The TXD(––) instruction can be used to transmit data from the PC’s data area to the host computer. There is no response from the host computer. The TXD(––) instruction will be executed after the response has been transmitted if TXD(––) is executed while a response to a Host Link command is being returned to the host computer.

Host	No response
computer

PC

4-4-2 Example Programs

@Unit No. Header code

Text

FCS

Terminator

Command Transmission The following type of program must be prepared in the host computer to receive the data. This program allows the computer to read and display the data re- ceived from the PC while a Host Link read command is being executed to read data from the PC.

Example Program for

FCS

10	’CQM1H	SAMPLE PROGRAM FOR EXCEPTION
20	CLOSE 1
30	CLS
40	OPEN ”COM:E73” AS #1
50	KEYIN
60	INPUT ”DATA ––––––––”,S$
70	IF S$=” ” THEN GOTO 190
80	PRINT ”SEND DATA = ”;S$
90	ST$=S$
100 INPUT		”SEND OK? Y or N?=”,B$
110 IF B$=”Y” THEN GOTO 130 ELSE GOTO KEYIN
120 S$=ST$
130 PRINT		#1,S$	’Sends command to PC
140 INPUT		#1,R$	’Receives response from PC
150 PRINT		”RECV DATA = ”;R$

160IF MID$(R$,4,2)=”EX” THEN GOTO 210 ’Identifies command from PC

170IF RIGHT$(R$,1)<>”
” THEN S$=” ”:GOTO 130

180GOTO
KEYIN

190CLOSE 1

200END

210PRINT ”EXCEPTION!! DATA”

220GOTO 140

This example shows a BASIC subroutine program for executing an FCS check on a frame received by the host computer.

400 *FCSCHECK

410L=LEN(RESPONSE$)

420Q=0:FCSCK$=” ”

430A$=RIGHT$(RESPONSE$,1)

440PRINT RESPONSE$,A$,L

450IF A$=”*” THEN LENGS=LEN(RESPONSE$)-3

ELSE LENGS=LEN(RESPONSE$)-2

460FCSP$=MID$(RESPONSE$,LENGS+1,2) ’ . ... FCS data received

470FOR I=1 TO LENGS ’ . .......... Number of characters in FCS

48