IGS-NT-BC, SW Version 1.2.0,
©ComAp – January 2019
IGS-NT-BC-1.2.0 Reference Guide.PDF
33
Redundant systems using CAN bus
This system uses the CAN bus for detection whether the main controller is operational or not. If the
redundant controller has not received two consequent messages from the main one (~100ms) it will take
over the system control - it activates the binary output C
TRL
HB
EAT
FD, which has to be wired in such a way,
that it disconnects the dead main controller from the control, connects the redundancy controller instead and
activates it by deactivation of the binary input E
MERG
.
MANUAL
.
As there can be up to 16 pairs of controllers at the CAN bus it is necessary to select which main controller
(address) belongs to which redundant one. The setpoint
ProcessControl:Watched Contr
is used for this
purpose. It must be adjusted to address of the respective main controller in each redundant controller and it
must be adjusted to 0 in each main controller.
C
AUTION
!
Correct wiring of all inputs and outputs that should be used both by the main and the redundant controller
needs to be done. Please refer to the corresponding chapter for wiring of binary inputs and outputs.
Do not use Shared Binary Inputs/Outputs for C
TRL
HB
EAT
FD
->
E
MERG
.
MANUAL
connection since the failed
controller may not interpret it correctly!
VPIO
VPI
VPO
CtrlHBeat FD
Emerg. manual
C
A
N
LOG BOUT
LOG BIN
Watched contr = X
Setpoint
Emerg. manual
LOG BIN
C
A
N
BOUT
BIN
LOG BIN
MAIN CONTROLLER
REDUNDANT CONTROLLER
Contr. Address = X
Setpoint
Figure:
Example of redundancy function
In the figure above the signal of logical function CtrlHBeat FD is used to disable the main controller if it is lost
from CAN bus or CAN bus communication from that controller becomes erratic. It is used also to disable the
redundant controller when the communication on CAN bus is alright (it is negated). For more information on
Virtual Binary Inputs and Outputs (VPIO) please refer to the chapter about Shared Binary Inputs and Outputs
and Virtual Binary Inputs and Outputs.
N
OTE
:
Use pulse signals for control of circuit breakers. MCB
ON
C
OIL
,
MCB
OFF
C
OIL
,
MGCB
ON
C
OIL
and MGCB
OFF
C
OIL
should be used to prevent sudden opening for a short period of time when the controller fails and
to ensure proper function of redundancy.
Force value
– step by step guide
In this chapter there is complete step by step guide which shows how to use Force value function of the
controller.
Forcing of values is used to change particular setpoint temporarily by activation of related Binary Input. This
is used to change function of controller under given conditions (e.g. there are two different periods during the
day when Export limit given by distribution network is required or not).
W
ARNING
!
