Rockwell Automation 2755 Enhanced Decoder Series B User Manual

Page 168

12–6

Configuration: Host Communications

Publication 2755-833

Large Buffer

Field Type Options

Select

Yes
No

Enables or disables use of the 8K byte buffer on the HOST port. The
default is No, which disables use of this buffer.

The 8K byte buffer allows the decoder to decode and buffer
messages to the host. This feature is useful for applications where the
host is incapable of handling high burst rates of data from the
decoder. If No is selected, the decoder will only buffer one message.

ATTENTION: Do not use the large buffer if the data
sent to the host must be coordinated with the output
modules, because the buffering may delay receipt of
the data by the host.

Send Message to Host

Field Type Options

Select

At End of Trigger
Immediately After
Valid Package

Specifies when the decoder sends data to the host or activates an
output module. The default is At End of Trigger.

The end of trigger condition is determined by the decode mode. The
end of trigger conditions for the triggered decode modes are:

Timing

Host

Package Detect

Internal Timer

End of Trigger
(send message to

o t

Stop scan character

Detect signal goes
inactive

host
at end of trigger)

No-read timer ex-
pires

Immediately After
Valid Package

Symbols/package
count met

The response mode for the continuous and continuous/unique decode
modes is always Immediately After Valid Package. The decoder
sends data and activates the outputs immediately after a valid
package (symbols/package count is met) or a no-read, whichever
comes first. Use this mode for maximum speed.