Hnet Interface - ABB Symphony Harmony Series Instruction

Memory

Hnet Interface

WBPEEUI210507A0
The module utilizes two types of memory: static-RAM (SRAM)
memory and flash-ROM memory.
NOTE: The electronic ID (i.e., device ID) of the block is stored in ROM memory.
The SRAM memory for microprocessor use is a 72-pin SIMM
SRAM module mounted on the processor board. This memory
provides temporary storage to perform calculations and data
manipulation. The Hnet interface also uses a shared SRAM
memory to store received messages and messages to be trans-
mitted.
The flash-ROM memory stores the operating firmware (i.e.,
boot and application programs). This type of memory provides
the ability to download updated firmware without having to
physically replace discrete components. Refer to
for firmware download procedures.
Hnet is the redundant, serial communication protocol over
which the SIM-100 block communicates with the Harmony
controller. Figure 2-4
module circuitry. The Hnet interface encodes and transmits
Hnet messages, receives and decodes Hnet messages, and
monitors Hnet status.
DATA A N D
C O N T R O L
H N E T
C O N T R O L
Figure 2-4. Hnet Interface
The Hnet control portion of the interface is a custom, applica-
tion-specific integrated circuit (ASIC). This circuit manages the
serial communication protocol between the SIM-100 block and
the controller. It also performs data integrity checks. The inter-
face checks for the following message errors: data
details the Hnet interface section of the
T R A N S C E IV E R R E LAY
A A
T R A N S C E IV E R R E LAY
B B
Description
Appendix B
H N E T A
H N E T B
T 0 0 5 6 1 B
2 - 5