Emerson PACSystems Versamax - Read Map Reply

PACSystems VersaMax Genius Network Interface User Manual Section 5
GFK-1535D Jan 2023
Configuration 84
5.3 Read Map Reply
Subfunction Code: 2B hex
An NIU sends this reply datagram after receiving a Read Map datagram.
It contains the previously configured NIU network map addresses. The
network map defines the NIU memory locations of the data that is
exchanged on the Genius bus. It provides no information about the I/O
assignments of individual I/O modules in the station. However, the
checksums indicate whether the overall configuration has been changed.
Byte No.
Byte Description
0
Not used
1
Starting reference for discrete input ( I ) data (LSB)
2
Starting reference for discrete input ( I ) data (MSB)
3
Length of discrete input ( I ) data (in bytes)
4, 5
Starting reference of analog input ( AI ) data
6
Length of analog input ( AI ) data (in bytes)
7, 8
Starting reference of discrete output ( Q ) data
9
Length of discrete output ( Q ) data (in bytes)
10,11
Starting reference of analog output ( AQ ) data
12
Length of analog output ( AQ ) data (in bytes)
13
8-bit Additive Checksum Unused (always 0)
14, 15
16-bit CRC Critical Checksum (lsb in 14, msb in 15) READ ONLY
16
8-bit Additive Checksum. Unused (always 0)
17, 18
16-bit CRC Non-Critical Checksum (lsb in 17, msb in 18) READ ONLY
Starting references for I, AI, Q, and AQ memory are returned. For each
memory type, a data length is also supplied. If a length is zero, the
associated starting reference can be ignored; it is not meaningful.