4-54 I/O Communication and Control 5702269-C
Advanced Energy
®
AE Bus Protocol
The AE Bus protocol uses pure binary data (nothing is coded ASCII) and is designed
to facilitate direct communications between a host computer and the Pinnacle Plus+
power supply.
The AE Bus message packet combines chunks of information in such a way that much
information can be sent over communication lines at one time. Five types of
information (or “Fields”) make up message packets (Figure 4-16):
• Header (address and length of data field)
• Command (see the command list later in this chapter)
• Optional length byte
•Data
• Checksum (error checking)
Figure 4-16 shows the organization of these fields in the AE Bus message packet. The
subsequent paragraphs describe each field.
Note: The message packet features this structure whether the message originates at
the host computer (master node) or the Pinnacle Plus+ unit.
Figure 4-16. Graphic representation of an AE Bus message packet
HEADER
The first byte in each packet contains two pieces of information: five bits contain the
packet address, and three bits contain the data byte count. If the message packet
originates with the host computer (master), the address specifies the packet's
destination (to a Pinnacle Plus+ unit, for example). If the packet is going to the host,
the address specifies the packet's origin (from the Pinnacle Plus+ unit). The address
section of the Header field is five bits long, which allows a total of 32 distinct
76543210765432107654321076543210 7654321076543210765432101076543
Data (0-255 bytes)
Command
0-FFh
Header
5-bit address
3-bit length
Optional Checksum
1138
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