Envoy ACP/XF Application Programming Manual

Normal Response Mode (NRM) Protocols
EnvoyACP/XF Application Programming Manual–132179
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Sending Mode-Setting Commands
•
One specific tributary station
•
Only disabled tributary stations
Sending to All of the Tributaries
When sending to all stations, EnvoyACP/XF makes one complete pass through the
defined station list. If all tributaries respond properly (UA), the operation completes with
CCE.
If one tributary responds improperly or not at all, EnvoyACP/XF retries polling that
station up to the configured number of times. If EnvoyACP/XF still does not receive a
correct response, it places the tributary on the nonresponding list and the operation
completes with a CCL and a file-system error code of either 171 or 172. To find out
which tributary is at fault, your error-handling procedure must issue a READ call. The
READ request completes with a CCL and a file-system error 171; bits 8 through 15 of
the returned MCW provide an index into the station list and contain the cardinal number
of the station in an error-stop state. You must continue issuing READ procedures until
the MCW indicates that there are no further queued items to be read.
If an error occurs, EnvoyACP/XF continues sending commands to the remaining stations
on the poll list. EnvoyACP/XF adds failed stations to the nonresponding stations list. At
this point, your application can perform either of the following actions:
•
Retry the CONTROL operation immediately (after reenabling the failed stations
using either CHANGELIST or DEFINELIST).
•
Use the slow-poll implementation, that is, retrying the CONTROL operation after a
reasonable delay (1 minute). The CONTROL parameter 4 allows you to send
selectively SNRM or DISC commands to stations that are on the disabled list.
Sending to Subset of Tributaries
To send the command frame to a subset of tributaries in the station list, perform the
following procedures:
1. Call CHANGELIST and set the poll-bit state to no poll for those stations to which
you do not want to send the command.
(See the CHANGELIST procedure in the Guardian Procedure Calls Reference
Manual for information on how to specify no poll for specific stations.)
2. Issue the CONTROL call.
Sending to a Specific Tributary
To send to a specific station, you can select the station by using the value in the
parameter word; if the high-order bit is set, the low-order byte is the station index.
For CONTROL 18, the inclusion of the offline state is implied. Also, EnvoyACP/XF
clears any partially disabled condition.