GE GFK0579B 用户手册

This datagram is used to read the Series 90–70 I/O references assigned to  a Remote
I/O Scanner, and its Remote Drop ID.

Data Field Format:  none

A Remote I/O Scanner sends this reply datagram after receiving a Read Map
datagram.  It contains the Series 90–70 I/O references assigned to the Remote I/O
Scanner, and its Remote Drop ID.  It provides no information about the I/O
assignments of individual I/O modules in the remote drop.  However, the checksum
supplied indicates that the overall configuration remains unchanged.

0

Remote Drop ID

1

Starting reference %I (LSB)

2

Starting reference %I (MSB)

3

Length of %I data (in bytes)

4, 5

Starting reference %AI

6

Length of %AI data (in bytes)

7, 8

Starting reference %Q

9

Length of %Q data (in bytes)

10,11

Starting reference %AQ

12

Length of %AQ data (in bytes)

13

8–bit  Additive Checksum READ ONLY

14, 15

16–bit LRC Checksum (lsb in 14, msb in 15) READ ONLY

The Remote Drop ID is a unique number between 16 and 254 that identifies the remote
drop.

Starting references in %I, %AI, %Q, and %AQ memory may be returned.  For each
memory type, a data length is also supplied.  If zero, the associated starting reference
can be ignored; it is not meaningful.

This datagram allows a CPU to send Series 90–70 I/O addresses and a Remote Drop ID
to a Remote I/O Scanner. If the Remote I/O Scanner receives this message, and its
configuration is not currently protected (by means of the Hand–held Monitor’s Con-
figuration Protect feature), the I/O modules present in the remote drop are automati-
cally configured. Data format for this datagram is the same as Read Map Reply.

The checksum must be included in the message, even though its values are ignored.