Use Case and Reaction Time

The HA-CS31 system performs a switch over when the primary CPU is powered off, crashed or stopped or if the primary CS31 bus is disconnected. The total switch over time depends on the use case. The following table gives an overview of the switch over times assuming that HA cycle = CS31 cycle time (as indicated in Automation_Builder) or at least 30 ms according to the recommendation. After CI590 switchover period the outputs will be written from the new CPU. CI590 LED will be steadily green after CPU switch over period.

	Capacitor discharge period	CI590 switch over period	CPU switch over period, afterwards remaining CI590 are switched over
Primary CPU powered off	Depending on system size	£ 4 CS31 cycles	Not relevant, all CI590 already switched over
Primary CPU stopped	0	£ 2 CS31 cycles	Not relevant, all CI590 already switched over
Primary CS31 bus cut near CPU	0	£ 4 CS31 cycles	35 HA cycles
Primary CS31 bus cut at local CI590	0	£ 4 CS31 cycles	35 HA cycles

Details are described in the following sections:

Primary CPU Off or Primary CPU Crash

Reaction	Switch over to secondary CPU. All CI590 are immediately switched over.
Total switch over time	CI590 switch over period (£ 4 CS31 cycles).
Comment	In case of power off there is a capacitor discharge period before CI590 switch over period. Duration depends on the system size. Outputs are frozen during CI590 switch over period. It takes some more HA cycles until the other CPU takes over primary status. However, this is not relevant for the process, because all CI590 were already switched over individually in the first CI590 switch over period.
Diagnosis message on function block	Primary CPU: Power OFF Secondary CPU: HA_CS31_CONTROL: 16#101B (remote CPU failure: other CPU is OFF or out of order.)
Diagnosis message on CI590-CS31 LEDs	“CS31 A” OFF, “CB” ON, “RUN A” OFF, “RB” ON, “SYNC-ERR” RED (Blinking), “S-ERR” RED (Blinking).

Primary CPU Stop

Reaction	Switch over to secondary CPU. All CI590 are immediately switched over.
Total switch over time	CI590 switch over period (£ 2 CS31 cycles).
Comment	Outputs are frozen during CI590 switch over period. It takes some more High Availability cycles until the other CPU takes over primary status. However, this is not relevant for the process, because all CI590 were already switched over individually in the first CI590 switch over period.
Diagnosis message on function block	Primary CPU: STOP Secondary CPU: HA_CS31_CONTROL: 16#101B (remote CPU failure: other CPU is OFF or out of order.)
Diagnosis message on CI590-CS31 LEDs	“CS31 A” ON (Blinking), “CB” ON, “RUN A” OFF, “RB” ON, “SYNC-ERR” RED (Blinking), “S-ERR” OFF.

Secondary CPU Off or Secondary CPU Crash

Reaction	No switch over
Total switch over time	N.A.
Comment	Process continues
Diagnosis message on function block	Primary CPU: HA_CS31_CONTROL: 16#101B (remote CPU failure: other CPU is OFF or out of order.) Secondary CPU: Power OFF
Diagnosis message on CI590-CS31 LEDs	“CS31 A” ON, “CB” OFF, “RUN A” ON, “RB” OFF, “SYNC-ERR” OFF, “S-ERR” ON (Blinking).

Secondary CPU Stop

Reaction	No switch over
Total switch over time	N.A.
Comment	Process continues
Diagnosis message on Function Block	Primary CPU: HA_CS31_CONTROL: 16#101B (remote CPU failure: other CPU is OFF or out of order.) Secondary CPU: STOP
Diagnosis message on CI590-CS31 LEDs	“CS31 A” ON, “CB” ON (Blinking), “RUN A” ON, “RB” OFF, “SYNC-ERR” OFF, “S-ERR” OFF.

Primary CS31 Bus Off / Disconnected / Short Circuit near CPU / No Module Connected

Reaction	Switch over to secondary CPU. All CI590 from the broken CS31 bus are immediately switched over. After the CPU switch over period all CI590 from the other CS31 lines are switched over.
Total switch over time	CI590 switch over period (£ 4 CS31 cycles) + CPU switch over period (~ 35 HA cycles)
Comment	Outputs are frozen during CI590 switch over period. It takes ~ 35 HA cycles until the other CPU takes over primary status. Thus short disturbances of the CS31 bus cannot cause an unintended switch over.
Diagnosis message on function block	Primary CPU: HA_CS31_CONTROL: 16#2005 (CS31 Bus failure), HA_CS31_DIAG / HA_CS31_DIAG_VIA_CM574: 16#1021 (one or more CI590-CS31-HA slave(s) is inactive) Secondary CPU: STOP
Diagnosis message on CI590-CS31 LEDs	“CS31 A” ON, “CB” ON (Blinking), “RUN A” ON, “RB” OFF, “SYNC-ERR” OFF, “S-ERR” OFF.

Primary CS31 Bus Off / Disconnected / Short Circuit at local CI590/ some Modules still Connected

Reaction	Switch over to secondary CPU. All disconnected CI590 are immediately switched over. After the CPU switch over period all remaining CI590 of the same CS31 line and all CI590 from the other CS31 lines are switched over.
Total switch over time	CI590 switch over period (£ 4 CS31 cycles) CPU switch over period (~ 35 HA cycles)
Comment	Outputs are frozen during CI590 switch over period. It takes ~ 35 HA cycles until the other CPU takes over primary status. Thus short disturbances of the CS31 bus cannot cause an unintended switch over.
Diagnosis message on function block	Primary CPU: HA_CS31_CONTROL: 16#1021 (own CI590-CS31-HA slave failure (missing module), HA_CS31_DIAG / HA_CS31_DIAG_VIA_CM574: 16#1021 (one or more CI590-CS31-HA slave(s) is inactive) Secondary CPU: HA_CS31_CONTROL: 16#201B (remote CS31 Bus failure: other CPUs’ CS31 Bus is out of order)
Diagnosis message on CI590-CS31 LEDs	“CS31 A” OFF, “CB” ON, “RUN A” OFF, “RB” ON, “SYNC-ERR” ON, “S-ERR” ON (Blinking).

Secondary CPU CS31 Bus Disconnected / Short Circuit / at least one Module is Disconnected\

Reaction	No switch over
Total switch over time	N.A.
Comment	Process continues
Diagnosis message on function block	Primary CPU: HA_CS31_CONTROL: 16#201B (remote CS31 Bus failure: other CPUs’ CS31 Bus is out of order) Secondary CPU: HA_CS31_CONTROL: 16#1021 (own CI590-CS31-HA slave failure (missing module), HA_CS31_DIAG / HA_CS31_DIAG_VIA_CM574: 16#1021 (one or more CI590-CS31-HA slave(s) is inactive.)
Diagnosis message on CI590-CS31 LEDs	“CS31 A” ON, “CB” OFF, “RUN A” ON, “RB” OFF, “SYNC-ERR” OFF, “S-ERR” ON (Blinking).

ETHERNET Cable Disconnected or no ETHERNET Communication

Reaction	No switch over
Total switch over time	N.A.
Comment	Process continues
Diagnosis message on function block	Primary CPU: HA_CS31_CONTROL: 16#2013 (no ETHERNET Link) Secondary CPU: HA_CS31_CONTROL: 16#2013 (No ETHERNET Link)
Diagnosis message on CI590-CS31 LEDs	CI590-CS31 LEDs status: “CS31 A” ON, “CB” ON, “RUN A” ON, “RB” OFF, “SYNC-ERR” OFF, “S-ERR” OFF (considering PM1 is Primary).

One or more CI590-CS31-HA are Off or not connected to both CPUs

Reaction	No switch over
Total switch over time	N.A.
Comment	Process continues on existing module according user’s choice
Diagnosis message on function block	Primary CPU: HA_CS31_CONTROL: 16#2006 (fault on both local and remote CPU), HA_CS31_DIAG / HA_CS31_DIAG_VIA_CM574: 16#1021(one or more CI590-CS31-HA slave(s) is inactive),HA_CS31_DIAG_VIA_CM574: 16#1021(one or more CI590 are inactive) Secondary CPU: HA_CS31_CONTROL: 16#2006 (fault on both local and remote CPU), HA_CS31_DIAG / HA_CS31_DIAG_VIA_CM574: 16#1021(one or more CI590-CS31-HA slave(s) is inactive), HA_CS31_DIAG_VIA_CM574: 16#1021 (one or more CI590 are inactive)
Diagnosis message on CI590-CS31 LEDs	“CS31 A” ON, “CB” ON, “RUN A” ON, “RB” OFF, “SYNC-ERR” OFF, “S-ERR” OFF.

CM574-RS is not in RUN mode in Primary

Reaction	Switch over to secondary PLC
Total switch over time	5 ms
Comment	Outputs freeze to last state during switch over time. Then process continues on secondary CPU.
Diagnosis message on function block	Primary CPU: HA_CS31_CONTROL: 16#2005 (CS31 Bus failure), HA_CS31_DIAG_VIA_CM574: 16#2013 (error in DPRAM communication between CM574-RS and PM5xx) Secondary CPU: HA_CS31_CONTROL: 16#201B (remote CS31 Bus failure: other CPUs’ CS31 Bus is out of order)
Diagnosis message on CI590-CS31 LEDs	“CS31 A” ON (Blinking), “CB” ON, “RUN A” OFF, “RB” ON, “SYNC-ERR” ON (Blinking), “S-ERR” OFF.

CM574-RS not in RUN mode in Secondary

Reaction	No switch over
Total switch over time	N.A.
Comment	Process continues
Diagnosis message on function block	Primary CPU: HA_CS31_CONTROL: 16#201B (remote CS31 Bus failure: other CPUs’ CS31 Bus is out of order) Secondary CPU: HA_CS31_CONTROL: 16#2005 (CS31 Bus failure), HA_CS31_DIAG_VIA_CM574: 16#2013 (error in DPRAM communication between CM574-RS and PM5xx)
Diagnosis message on CI590-CS31 LEDs	“CS31 A” ON, “CB” ON (Blinking), “RUN A” ON, “RB” OFF, “SYNC-ERR” OFF, “S-ERR” OFF.

CM574-RS not in RUN mode in both systems

Reaction	No switch over as fault is in both system
Total switch over time	N.A.
Comment	-
Diagnosis message on function block	Primary CPU: HA_CS31_CONTROL: 16#2006 (fault on both local and remote CPU), HA_CS31_DIAG_VIA_CM574: 16#2013 (error in DPRAM communication between CM574-RS and PM5xx) Secondary CPU: HA_CS31_CONTROL: 16#2006 (fault on both local and remote CPU), HA_CS31_DIAG_VIA_CM574: 16#2013 (error in DPRAM communication between CM574-RS and PM5xx)
Diagnosis message on CI590-CS31 LEDs	“CS31 A” ON (Blinking), “CB” ON (Blinking), “RUN A” ON (Blinking), “RB” OFF, “SYNC-ERR” OFF, “S-ERR” ON (Blinking).

Manual Switch over by Users

Reaction	Switch over to secondary CPU at user’s request
Total switch over time	N.A.
Comment	Process continues, primary and secondary CPUs are swapped
Diagnosis message on function block	Primary CPU: No Error Secondary CPU: No Error
Diagnosis message on CI590-CS31 LEDs	“CS31 A” ON, “CB” ON, “RUN A” OFF, “RB” ON, “SYNC-ERR” ON, “S-ERR” OFF (Considering Manual switch over request to PM1).