1747-6.22, Backup Scanner User Manual

Transferring Data over
the High-Speed Serial
Link (HSSL)
Module Control and Status Word 6-93
• RIO Communication: This bit is set when a problem occurs
with the RIO link in the local (bit 4) or remote (bit 12) 1747-
BSN module. The type of problem that may occur is different for
primary and secondary systems (as shown below). The normal
state of this bit is OFF):
1. Primary mode: the channel is faulted or has
communication errors;
0. Secondary: no communication could be seen by this
module in the RIO link. This indicates that the primary
RIO link is not working or that a problem exists in the
RIO connection to the secondary 1747-BSN module;
• Processor Fault: This bit is set when one of the processors
(SLC 5/0x), either the local (bit 5) or remote (bit 13), is in failure
or is in Program or Test mode. The normal state of this bit is
OFF;
• Primary/Secondary System: This bit is set when the local (bit
6) or remote (bit 14) system is in the primary mode, otherwise
the system is in the secondary mode. Bits 6 and 14 are never set
at the same time. During power-up or switchover time, these bits
can be clear at the same time. The normal operation is with one
bit set for the primary system and one bit clear for the secondary
system.
Two M0 file words and one M1 file word are used to control the
transfer of data from the primary SLC processor to the secondary
SLC processor. This link should be used to transfer internal processor
data that must be kept current in the secondary processor in the event
that a switchover takes place, making the secondary processor the
primary processor. Actual input data from remote I/O chassis need
not be transferred over this link since the secondary BSN allows the
secondary processor to receive this data from the remote I/O network
in a “listen mode”. Outputs are only controlled by the primary
processor.
The three words used to accomplish data transfer over the HSSL are:
1. M0:s.3410: Data Transfer Control Word (DTCW)
This word is used by the primary processor to initiate the transfer
of data to the primary BSN. This data is ultimately transferred to
the secondary BSN over the HSSL, then to the secondary
processor.
2. M1:s.3410: Data Transfer Status Word (DTSW)
This word is used in both the primary system and the secondary
system to affect the transfer of data on the HSSL.
Publication 1747-6.22