6100 MPS-B Programming Manual

WRITING APPLICATIONS THAT USE 6100 MPS-B
READ Request
READ Request
The READ request permits your application process to either poll
all stations sequentially (sequential poll) or poll a specific
station (specific poll).
For sequential polling, only stations that are enabled or are not
on the nonresponding list are polled. Polling continues if a
polled station responds with EOT. If a polled station responds
with a message, the READ request terminates.
A specific poll is performed even if the specified station is
disabled, or on the nonresponding list. The READ request is
terminated when the station responds with EOT, a message, or does
not respond (timeout). If the station is on the nonresponding
list at the time of the poll and responds with either EOT or a
message, it is removed from the nonresponding list.
The request buffer format is:
Function := 65
Modifier := 0 if sequential poll,
1 if specific poll using station index,
2 if specific poll using free format, or
3 if ADM-2 SEND function using ENVOY format
Request ID := A unique value from 1 to 32767,
application-dependent
Text Out := 0 if Modifier is 0,
2 if Modifier is 1 (for MCW),
n if Modifier is 2 (n is dependent on the free
format poll sequence type), or
7 if Modifier is 3 (ADM-2 SEND function)
Text In := Expected or maximum length of message to be read
(must be equal to or less than 2048)
Text := Null when Modifier is 0,
MCW when Modifier is 1,
MCW followed by free format poll sequence when
Modifier is 2, or
MCW followed by SEND function poll sequence if
Modifier is 7
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