Remote-processing RPC-330 Manual do Utilizador descarregar pdf (Página 24)

DIGITAL I/O SECTION 6

Page 6-3 RPC-330

LINE function and statement at J3 is used with MPS-XX

opto rack. It accesses a module according to the position

number printed on the MPS board. Lines are numbered

from 100 to 123. The opto m odule number used in this

command is computed by adding 100 to the board

position number. LINE also accesses L0-L8 on P2 and

P6.

The LIN E B function and statement is used to access

digital I/O lines 8 bits at a time. T he address for port A

is 0, B is 1, and C is 2. The segment number is 3.

LINE # function and statement accesses lines according

to the pin number at J3. J3 lines are numbered from 101

to 125. The line number used in this com mand is

computed by adding 100 to the connector pin number.

Line 102 is not allowed as it is the + 5V supply. See

Table 6-1 to correspond a pin number to a port and opto

rack position.

P6 lines are numbered 0 to 7, and correspond to the

terminal number on the board. L8 at P2 is a high

current output and is accessed using LINE 8. The status

of ISOA/B is returned using LINE 8 function.

LINE, LINE B and LINE # return a ' true' logic level.

A ' 1' indicates + 5 volts or high and a '0' is low or

ground. LINE B and LINE # output true logic levels.

LINE, however, outputs inverted logic. In order to turn

on an opto module, a line must go low. However,

turning on a module using LINE, you must specify a ' 1' .

100 LINE 118,1 :REM Turn opto 118 ON

110 LINE 118,ON :REM Turns opto 118 ON

120 LINE#104,0 :REM also turns 118 ON

ON LIN E is a multitasking command. W hen active, the

RPBASIC oper ating system checks the specified line

every 5 ms. If the line changed state from the previous

scan, a software interr upt is set. Upon completion of the

current BASIC command (and assuming no other

interrupts are active), program execution branches to a

specified subroutine. This command is useful for

monitoring lines, such as limit or door switches, that

may not change often or when the program structure

make it unwieldy to check lines frequently.

Another multitasking command, ON COUNT, causes the

operating system to check the specified line every 5 m s.

Up to 8 lines are monitored. If the line changed from a

high-to-low state, a counter is incremented. M aximum

counting rate is effectively 95 Hz. This command has

two variations. One causes a software interr upt when a

specified num ber of counts is reached. Another simply

counts pulses at a line. The C OUNT function returns

the number of pulses since ON COUNT was initiated.

See Appendix A for command information.

ON C OUN T and O N LIN E do not necessarily h ave to

be input lines. They can be outputs controlled by

another part of the program.

High Current Output

Eight lines at J3 can be used as high current driver s.

These outputs switch loads to ground. Outputs are

controlled by Port B on the 82C55.

Logic outputs are inverted. That is, when a 1 is written

(using the LINE# comm and) to the high current port, the

output is switched on and goes low.

The output driver chip, U 12, can be replaced with a DIP

shunt jumper so it is like the other lines at J3. To do

this, r emove U12. Install a DIP shunt so pin 1 goes to

pin 18. Pins 9 & 10 are open.

NOTE: Outputs at the high current lines are not

compatible with TTL logic levels and should not

be used to drive other logic devices.

Each of the high current outputs can sink 500 ma at 50V.

However, package dissipation will be ex ceeded if all

outputs are used at the maximum rating. The following

conservative guidelines assume the number of outputs

are on simultaneously:

# of outputs Maximum current

on per output

1 500 ma

2 400 ma

3 275 ma

4 200 ma

5 160 ma

6 135 ma

7 120 ma

8 100 ma

The ther mal time constant of the package is very short,

so the number of outputs that are on at any one time

should include those that overlap even for a few

milliseconds.

Incandescent lamps have a "cold" current of 11 times its

operating current. Lamps requiring more than 50 ma

1 2 ... 19 20 21 22 23 24 25 26 27 28 29 ... 47 48

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