Specifications

80 209351 REV B Operations Manual, Redundant System Controllers
7.2.4 Timing issues
There is no maximum specification on the inter-character spacing in messages. Bytes
in messages to amplifier units may be spaced as far apart as you wish. The amplifier
will respond as soon as it has collected enough bytes to determine the message.
Generally, there will be no spacing between characters in replies generated by units.
The maximum length of the packet sent to the amplifier node should not exceed 64
bytes, including checksum and frame sync bytes. Inter-message spacing, must be
provided for good data transmission. The minimum spacing should be 100 ms. This
time is required for the controller to detect a “Line Cleared” condition with half duplex
communications. Maximum controller respond time is 200 ms.
J4 Main or
J9 Ethernet
J5 Local
Request Frame A
Response Frame A
Request Frame B
Response Frame B
P
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o
p
a
g
a
t
i
o
n
d
e
l
a
y
1
-
5
0
m
S
P
r
o
p
a
g
a
t
i
o
n
d
e
l
a
y
1
-
5
0
m
S
Propagation delay 1 - 10 mS
Host PC
SSPA Subsystem
Protocol ID
0
Request ID
0 to 255
Command
0 - 1
Data T ag
6
Response Length
n = 11 + m
Data Length
11 to 11 + m
Header
4 Bytes
Command Preamble
6 Bytes
Request Frame B
11 to 11 + n Bytes
Trailer Checksum
1 Byte
Request Frame A
Protocol ID
0
Request ID
0 to 255
Command
0 - 1
Data Tag
0 - 4
Data Address
0 to 255
Data Length
m = 1 to 128
Header
4 Bytes
Command Preamble
6 Bytes
Data Field
0 to m Bytes
Trailer Checksum
1 Byte
Request Frame B
Protocol ID
0
Request ID
0 to 255
Command
2 - 3
Data T ag
6
Error Status
0 to 5
Data Length
11 + m
Protocol ID
0
Request ID
0 to 255
Command
2 -3
Data Tag
0 - 4
Error Status
0 to 5
Data Length
m = 1 to 128
Header
4 Bytes
Command Preamble
6 Bytes
ResponseFrame B
11 + n Bytes
Trailer Checksum
1 Byte
Response Frame A
Header
4 Bytes
Command Preamble
6 Bytes
Data Field
m Bytes
Trailer Checksum
1 Byte
Response Frame B
Figure 7-8: Packet Wrapper access to SSPA subsystem