Rockwell Automation 1785-Vx0B, D17856.5.9 PLC-5 VME VMEbus Programmable Controllers User Manual User Manual

Page 84

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Chapter 6

PLC-5/VME Processor
Communications Commands

6-15

Counter Example
The first byte is the data-type field (field a), the 6-byte element contains
the data (field b). Bits in the control word are:

If you see:

It means:

15

up counter enabled

14

down counter enabled

13

counter done

12

overflow

11

underflow

Timer Example
The first two bytes are the data-type field (field a), the 10-byte element
contains the data (field b). Bits in the control word are:

If you see:

It means:

15

timer enabled

14

timer timing

13

timer done

9 & 8

time base (10 for 1
second)

01100110

Bit 76543210

00000000

10000000

a

ID = 6 for control,
Size = 6 bytes

value: up counter enabled, not done,
no overflow/underflow, preset = 256,
accumulated = 7

00000000

00000001

00000111

Control byte (LS)

Control byte (MS)

Preset (LS)

(MS)

00000000

(MS)

Accumulated (LS)

01011001

Bit 76543210

00001010

00000000

a

ID = 5 for timer,
Size in next one byte

value: Timer enabled, timing, not done,
preset = 10 sec, accumulated = 9 sec.

11000010

00001010

00000000

Size = 10 bytes per element

00001001

Accumulated (LS)

00000000

Control byte (LS)

Control byte (MS)

Preset (LS)

Accumulated (MS)

Preset (MS)

b

00000000

00000000

00000000

00000000

Reserved

Reserved

Reserved

Reserved

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