Specifications

74 209351 REV B Operations Manual, Redundant System Controllers
7.2 Serial Communication
This section describes the normal communication protocol between the RCP2 and a
host computer over RS232/RS485 serial interface. Serial port settings on host
computer must be configured for 8-bit data at no parity, with 1 stop bit. Baud rate
should match selected baud rate parameter on RCP2 unit.
The unit will only respond to properly formatted protocol packets. Figure 7-4 shows the
basic communication packet. It consists of a Header, Data, and Trailer sub-packet.
7.2.1 Header Packet
The Header packet is divided into 3 sub-packets which are the Frame Sync,
Destination Address, and Source Address packets, as shown in Figure 7-5.
7.2.1.1 Frame Sync Word
The Frame Sync word is a two byte field that marks the beginning of a packet. This val-
ue is always 0xAA55. This field provides a means of designating a specific packet from
others that may exist on the same network. It also provides a mechanism for a node to
synchronize to a known point of transmission.
7.2.1.2 Destination Address
The destination address field specifies the node for which the packet is intended. It
may be an individual or broadcast address. The broadcast address is 0xFF or 0xAA
(see Section 7.2.5 Multiple Device Access). This is used when a packet of information
is intended for several nodes on the network. The broadcast address can be used in a
single device connection when the host needs to determine the address of the
amplifier. The RCP2 unit will reply with its unique address.
HEADER
(4 bytes)
DATA
(6-32 bytes)
Figure 7-4: Basic Communication Packet
TRAILER
(1 byte)
HEADER
(4 bytes)
DATA
(6-32 bytes)
TRAILER
(1 byte)
Frame Sync (2 bytes)
0xAA5
Destination Address
(1 byte)
Source Address
(1 byte)
Figure 7-5: Header Sub-Packet