6172 CAN Micro Controller Module AN005

This application example is not yet completely tested

64 bit input with CD 4021

This application example enables the user to use 64 CMOS digital inputs.

Eight pieces CD 4021 are used for this example.

This example uses the maximum capacity of one CANopen PDO, it can easily be expanded to 256 inputs, using 4 PDO's.

        header  "64 digital inputs AN005"
 
inputs: equ     16              ;64 inputs memory location (8 bytes)
 
strobe: equ     0               ;bitnummer of strobe of 4021's (OUT9)
 
;initialization sequence 
 
        sequence seq_0 
 
        resb    strobe          ;strobe inactive
        shspd   1               ;SPI shifter at 1.1 µS/bit 
        shpat   0               ;normal data, no shifted clock 
        srdy                    ;READY output active 
        enasq   0               ;enable sequences
        endsq
 
;read memory location 16..23 from 4021's
 
        sequence seq_3,1        ;executed every 10 mS
 
        seta    strobe          ;STROBE high for 7 µS
        resa    strobe          
        
        shom    inputs+7        ;first inputs 57-64
        shom    inputs+6        ;      inputs 49-56
        shom    inputs+5     
        shom    inputs+4     
        shom    inputs+3     
        shom    inputs+2     
        shom    inputs+1        ;      inputs 9-16
        shom    inputs          ;      inputs 1-8
        endsq
        
        end

Assuming that all 6172 objects are in their default state, the following objects need to be adjusted (if a PDO is used):

 

1	Subindex	Value	Description
PDO mapping of transmit PDO 1
1A00h	0	2	2 objects in transmit PDO 1
1A00h	1	61200520h	memory location 16-19
1A00h	2	61200620h	memory location 20-23
Enable PDO transmission on any change of memory location 16-23
6006	17	255	memory location 16
6006	18	255	memory location 17
6006	19	255	memory location 18
6006	20	255	memory location 19
6006	21	255	memory location 20
6006	22	255	memory location 21
6006	23	255	memory location 22
6006	24	255	memory location 23

The 64 digital inputs now can be read by:

• automaticaly after a change of any input value (transmit PDO1 is sent by 6172, minimal interval time set by sequence 1 interval time)
  (108 bits message)
• a PDO request of transmit PDO1
  (one 44 and one 108 bits message)
• reading object 6120, subindex 5 and 6, using two SDO reads.
  (4 x 108 bits message)
• reading object 6000h, subindex 16 up to 23, using eight SDO reads
  (16 x 108 bits messages)

Copy and Paste this part direct after the declarations in the canappl.bas program
this program can be found on the 6197 designers kit diskette or
ordered separately as service part together with one of our CAN products.  

APPLICATION:
 
'This simple program is made for one 6172 and a 6390 as CAN bus interface
'the following assumptions are done:
'- 6390 is connected to COM2
'- 6172 ID = 1, CANbus speed = 50 kBAUD
'- assembled sequence file is "AN005.seq"
 
'The 64 digital inputs are read using the PDO, if the PDO isn't received
'within 5 seconds, it is requested.
'The results are displayed as a 64 bit binary string
'this continues until the user presses enter
 
CLS
PRINT "CD Systems 6172 AN005 DEMO program"
PRINT
 
Activate6390 2, 19200                          '6390 works at COM2, 19200 BAUD
SetCANBUSSpeed 50                                         'CAN BUS at 50 kBAUD
 
C% = CheckSequence%(1, "AN005.seq")     'download sequence if not already done
 
C% = PutU8% (1, &h1A00, 0, 2)           '2 objects in transmit PDO1
C% = PutU32% (1, &h1A00, 1, &h61200520) 'transmit PDO1 from memory 16-19
C% = PutU32% (1, &h1A00, 2, &h61200620) 'transmit PDO1 from memory 20-23
 
C% = PutU8% (1, &h6006, 16, 255)         'enable transmit PDO on any change
C% = PutU8% (1, &h6006, 17, 255)
C% = PutU8% (1, &h6006, 18, 255)
C% = PutU8% (1, &h6006, 19, 255)
C% = PutU8% (1, &h6006, 20, 255)
C% = PutU8% (1, &h6006, 21, 255)
C% = PutU8% (1, &h6006, 22, 255)
C% = PutU8% (1, &h6006, 23, 255)
 
SendNMTCommand (1, 1)                   'node in operational state
 
BT = TIMER - 6                          'force immediate request
 
PDOCOB% = (1 + 384) * 32                'tx PDO1 COB ID shifted left 5 bits
 
DO
' send a transmit PDO1 remote request if nothing received after 5 seconds 
  IF (BT + 5) < TIMER THEN
     SendToCAN (CANIDS$ (PDOCOB% + &h10))
     BT = TIMER
  END IF
 
' check if the transmit PDO is received
  R$ = ReceiveFromCAN$
  IF LEN (R$) > 1 THEN                            'anything received?
     IF (CANIDR% (R$) AND &hFFE0) = PDOCOB% THEN  'PDO1 tx received?
 
       LOCATE 10,1
       FOR I% = 3 TO 10: M% = 1                   '8 bytes in PDO
        FOR B% = 1 TO 8                           '8 inputs in a byte
 
         IF (ASC(MID$(R$,I%)) AND M%) THEN PRINT "1"; ELSE PRINT "0";
         M% = M% * 2
        NEXT B%
       NEXT I%
 
       BT = TIMER
     END IF
  END IF
LOOP UNTIL INKEY$ = CHR$(13)
 
SendNMTCommand (1, 2)                             'stop node
 
DO                                'clear & ignore any received message
  R$ = ReceiveFromCAN$
LOOP UNTIL R$ = ""
 
END