1747-6.22, Backup Scanner User Manual

Program File 2
0000
0001
0002
Module Control and Status Word 6-97
The following ladder program example shows how to monitor the
status bits in the System Status Word (SSW) and in the Module Status
Word (MSW) that indicate which processor is in the primary mode
and which is in the secondary mode. This information is needed in
order to determine whether the local processor needs to execute the
primary system or the secondary system HSSL data transfer ladder
logic.
File 2 monitors the appropriate SSW and MSW bits and executes
subroutine 4 if the local system is in primary mode.
Note: It is recommended that the M1 and M0 file lengths for
the BSN be set to the maximum (5548). There is no
memory or speed penalty for creating the maximum
buffer size for these files in the BSN modules.
Copy the System Status Word (SSW) and the Module Status Word (MSW) from the BSN module to internal storage words in the SLC
processor every program scan. Bits 6 and 7 of the SSW word indicate whether this processor is Primary or Secondary at any given time.
Bits 6 and 14 of the MSW word indicate whether the local or remote system is in the Primary or Secondary mode respectively. Virtual
SSW and MSW words/bits are used to minimize M-file transfers, thereby minimizing their effects on the program scan time.
COP
Copy File
Source #M1:1.3400
Dest #B3:1
Length 2
This rung executes subroutine number 3 when the Local System is in the Secondary Mode. Subroutine 3 contains the logic which must
be executed to properly transfer HSSL data from the Secondary BSN Module to the Secondary SLC Processor.
Virtual SSW Bit:
when = 1, indicates Virtual MSW Bit: Virtual MSW Bit:
the local system is when = 1, indicates when = 1, indicates
in the Secondary the Local System is the Remote System is
Mode
in the Primary Mode in the Primary Mode
B3:1
B3:2
B3:2
JSR
Jump To Subroutine
7
6
14
SBR File Number U:3
This rung executes subroutine number 4 when the Local System is in the Primary Mode. Subroutine 4 contains the logic which must be
executed to properly transfer HSSL data from the Primary SLC Processor to the Primary BSN Module.
Virtual SSW Bit: Virtual MSW Bit: Virtual MSW Bit:
when = 1, the Local when = 1, indicates when = 1, indicates
System is in the the Local System is the Remote System is
Primary Mode in the Primary Mode in the Primary Mode
B3:1
B3:2
B3:2
JSR
Jump To Subroutine
6
6
14
SBR File Number U:4
0003 END
Publication 1747-6.22