43
11 Gateway Target
Device Failed to
Respond
Specialized for Modbus gateways. Sent when slave fails to
respond
Table 4 Modbus Exceptions Code
2. Modbus Memory Map for the Genesis Controller
The Genesis Controller actively listens for incoming TCP connections on port 502
from master device connected on the same network. Information stored in
Modbus memory map table can be accessed once a TCP communication
channel has been established. The memory map is described in this section and
referenced in the Global Settings and Circuit Settings tables.
Modbus read and write requests require a 16-bit data address to be referenced.
The limits of the data address referenced in a Modbus message are from 0 to
9998 or 0x0000 to 0x270E. The data address range corresponds to either a read-
only Function 04 Analog Input Registers 30001 to 39999, or the read/write
Function 03/06 Analog Output Holding Registers 40001 to 49999.
The Genesis Controller only allows Modbus 04 reads and 03/06 read/writes. The
Global Settings and Circuit Settings tables below describe the Genesis Controller
memory map in more detail.
The Global Settings Modbus Data Addresses are referenced as listed in the “Base
Memory Location” column of the Global Settings table. The Modbus Data
Address for the non-global read-only Function 04 and read/write Function 03/06
table entries can be computed by adding the circuit number to the Base Memory
Location.
Every Memory Location address as well as data length is two bytes or 16 bits.
Some DCS systems automatically put in an offset of plus or minus one for the
memory location. As such, the memory locations should be checked against a
known value to establish the automatic offset value.
Global Settings
Description
Allowed Values
Decimal Hex
4 10 0x00A
Logical Or of all alarm flags,
Read Only
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