ER-A570 (serv.man5). ERA570 Option Programming Manual - Sharp ECR Service Manual (repair manual). Page 8

Fig. 3-4 Types of packets

1

Normal sequence

2

Abnormal sequence-1
(when there is a single data error)

3

Abnormal sequence-2
(when there are six successive data errors)

Communication is disabled due to full retry counts . . . "PW-OFF"
(power off) will be printed on the master unit.

4

Abnormal sequence-3 (when ACK is in error)

5

Abnormal sequence-4 (when RACK is in error)

Full ACK retry counts. If RACK were not detected after five retries
to send ACK, it assumes RACK to be in error, and so the receiving
operation terminates normally.

6

Abnormal sequence-5
(receiving side not enabled to receive data)

when the IRC option is installed, an IRC terminal number must also
be supplied. This number is in the range of 1 to 254. The number is
specified in the PGM 2 mode at installation time. It is necessary to
specify an number for each device connected to the IRC including the
master. It should be noted that the IRC terminal number and the
register number are not related. Section 10 of this manual indicates
how this number is specified.

•

IRC terminal number (3 digits max.): *000 

∼

 254

*000: OFF line machine

•

Register number (4 digits max.): *0 

∼

 9999

    *0: can not be used in the IRC operation.

F

DATA
packet

DA

SA

0

CH NO

DLS

BCL

BCH

DATA

CRC

CRC

F

F

ACK
packet

DA

SA

1

CH NO

DLS

0

0

CRC

CRC

F

PACK
packet

NRDY
(Not ready)
packet

F

DA

SA

1

CH NO

DLS

0

0

CRC

CRC

F

F

DA

SA

1

CH NO

DLS

0

0

CRC

CRC

F

Control packet

Data

ACK

RACK

[Sequence]

[Receiving side]

Data

X

Data

ACK

RACK

(Retry)

NOTE:

X

Indicates an error.

15ms

(No ACK)

Data

X

Data

(Retry-1)

15ms

(No ACK)

X

Data

X

15ms

(No ACK)

(Retry-5)

(No ACK)

ACK

X

6ms

(No ACK)

ACK

Data

RACK

ACK-1

6ms

ACK-2

Data

RACK

X

ACK-5

Data

NRDY

1  5