Remote-processing RPC-52 Manuel d'utilisateur télécharger pdf (Page 19)

CHAPTER 6 DIGITAL AND OPTO PORTS

Page 17

using the PW M statem ent.

Jumper s W6 and W7 set the P WM output for opto

positions 0 and 1.

Jumper Position Description

W6 [1-2] Position 0 normal mode

W6 [2-3] Position 0 PWM output

W7 [1-2] Position 1 normal mode

W7 [2-3] Position 1 PWM output

When either position is jumpered for PWM output, none

of the LINE commands will work for that position.

PWM outputs are used to gener ate analog outputs.

When using one of the PWM positions, the

corresponding analog output should not be used.

G5 operation

The G5MOD statement can refer to an input or output

module, depending upon how it was used. Its use as an

input is discussed fir st.

Values from G5 modules are returned using the G5MOD

function. The syntax is

A = G5MOD(slot)

The slot number is from 0 to 3 or 100 to 123,

corresponding to the position on or off the boar d. T his

function returns a number from 0 to 256, corr esponding

to a resolution of 8 bits. The G5M OD function takes

about 7 ms to convert the input data.

WARNING:

Conversion time is approximately 7 m s. D uring this

time, all interrupts are turned off. Serial characters

will be missed at baud rates at and above 9600.

When installing and operating a G5 module in a

particular slot, make sure it is not turned "ON" as for a

G4 digital output module. If an output is turned on, then

no reading is received. When executing the CONFIG

LINE 0 statem ent, the slot the G5 m odule goes into

should be set as an input (1).

The program below takes 100 samples and stores it in an

array. The time to read and store 100 samples is 0.7

seconds, or 7 ms per sample.

10 DIM G(100)

20 FOR X = 0 TO 99

30 G(X) = G5MOD(1)

40 NEXT

Some applications require that measurements be made at

fixed intervals. T he ONTICK construct can be used to

take samples at timed intervals. The program below

reads 2 channels every tenth of a second and stores it

into an array. When the array fills, the tick timer stops.

10 DIM G(100)

20 DIM H(100)

30 ONTICK .1,100

40 REM This is a dummy loop

50 GOTO 40

100 G(I) = G5MOD(0)

110 H(I) = G5MOD(1)

120 PRINT I,G(I),H(I)

120 I=I+1

130 IF I=100 THEN ONTICK 0,100

140 RETI

The G5MOD statement also outputs to a module on an

external opto rack. It is not possible to use the internal

opto rack due to the electrical driver required. The

output number is from 0 to 4095.

To output to a G5 module, execute the following

command:

1000 G5MOD channel,value

channel is from 100 to 123 and corresponds to the

external opto rack position. value ranges fr om 0 to

4095.

Converting analog measureme nts

Input readings are converted to usable units of

measurement by performing scaling calculations in the

program. The G5MOD function returns values from 0

to 255. To change these readings to other units, use the

following calculation:

variable = K * G5MOD(slot)

K is a scaling constant. It is obtained by diving the

highest measurement unit number by 256.

Example:

You want to measure a 0 to 200 PSI pressure

transducer with a 0 to 5 volt output. Divide 200 by

256 to obtain the value of K.

K = 200 / 256

K = .78125

To obtain the final value for the equation in PSI:

100 V= .78125 * G5M OD(n)

DIGITAL I/O PORT

Digital I/O lines on the RPC-52 go to connector J4. I/O

interface is through an 82C55 chip.

This port can be used to interface additional opto

modules (using the MPS ser ies racks) , dr ive small

relays, solenoids, motors, or lamps, and provide general

purpose TTL I/O to other logic devices or mechanical

switches. The LINE command is used to access and

control this port.

The lines on J4 are divided into 3 eight bit gr oups. Ports

A and B can be configured as all inputs or outputs. Port

C can be progr amed a s one group of 8 inputs or outputs

or as two groups of four lines (upper and lower C ). The

four lines in upper and lower C can each be programmed

1 2 ... 14 15 16 17 18 19 20 21 22 23 24 ... 35 36

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Remote-processing RPC-52 Manuel d'utilisateur Page 19

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