Rockwell Automation 1772-LP3 PLC - 2/30 Programmable Controller Programming and Operations Manual - Manual (Page 181)

Report Generation
Chapter 9
9Ć13
Messages 1-6 use bits 10-15 of word 027 as message request bits. All other
messages use a user-defined file of message request bits for control. These
two categories will be discussed separately.
The upper byte of word 027 is used to control messages 1-6. Bit 027/10
is the request bit for message number 1; bit 027/11 is the request bit for
message number 2 and so on. Bit 027/16, the busy bit, is set on when
any of messages 1-6 are requested and will remain on until all requested
messages have been printed. Once all messages are generated, bit 027/17
will stay on for 300 ms and is then set off.
The upper byte of each message control word contains the request bits for
eight messages. There is an easy way to determine the message number
from the bit which requests it. The three right-most digits in the bit address
are coded to the message number. For example, if message number 312
were of interest, bit 12 of the third message control word would request
message 312 on a false-to-true transition (Figure 9.4).
Figure 9.4
Bit AddressĆMessage Number Relationship
Control Word
Number
Message
Numbers
Control Word
Address
0
1
2
3
4
5
6
7
010Ć017
110Ć117
210Ć217
310Ć317
410Ć417
510Ć517
610Ć617
710Ć717
200
201
202
203
204
205
206
207
The control word addresses are userĆselected.
Message number 3XX has a message request bit at address 203/XX. Message request bit 203/XX, when
enabled, will activate message number 3XX where XX are bit numbers 10Ć17.
Unlike messages 1-6 which share a common done bit (027/17), the
additional 64 messages each have a separate done bit. After a particular
message has been printed, the done bit is set until the user program resets
the request bit. Done bits are located in the lower byte of the message
control words. Figure 9.5 shows this relationship. For example, if 404/15
is the request bit for a message, the done bit is located at 404/05, 10
8
(one
byte) below the request bit.
9.3.1
Messages 1Ć6
9.3.2
Additional Messages