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PLC REDUNDANT SYSTEM (models: R3-NC3-x/W)
Bit 0 of RY(n+1) is assigned to designate control system or standby system. Set this bit from the host PLC to switch from the
PLC master control system to the standby system, or vice versa. The R3 module output (slave station) is controlled according
to the bit combinations as shown in the table below. No switching is required for the R3 input modules which continuously
send out data to both 'main' and 'sub' network modules.
RY(n+1) 0 = 0 : PLC master control system
RY(n+1) 0 = 1 : PLC standby system
R3 MAIN (RY(n+1) 0)
0
0
1
1
•Operation
R3 main network
RY (n+1) 0 = 0
RY (n+1) 0 = 1
Communication Status
Start
(1)
R3 sub network
RY (n+1) 0 = 0
RY (n+1) 0 = 1
1) When the PLC master control/standby system bit is undefined due to no communication, the both host PLCs function as
'standby' system for each of R3 'main' and 'sub' network modules. All contact outputs are off, and analog output modules
output -115%.
2) The master PLC communicates with the R3 main network module, while the standby PLC communicates with the R3 sub
network module.
3) When a wire breakdown is detected at the R3 main network, the output signal is held for the preset time period (Timer is
programmable with the PC Configurator Software, R3CON). After the time has been elapsed, the output is switched from
the R3 main to R3 sub network. Be sure to set an appropriate output signal to the R3 sub network before the switching.
The host PLC for the R3 main network is now functioning as standby system.
4) Once the PLC control is transferred to the standby system, it is necessary to set RY(n+1) 0 = 1 to the R3 main network in
order to prevent R3 output control automatically switched to the main network when the R3 main network is restored. If
it is set to RY(n+1) 0 = 0, the R3 output will be switched to the main network even when the PLC control is in the standby
system.
5) When both R3 main and R3 sub network modules are in communication, the output can be switched without delay by
setting RY(n+1) 0 values. Be sure to set an appropriate output signal to the network module before the control is switched
to it.
CONNECTION EXAMPLE for R3-NC3-x/W
Control
CPU
Master
Master
I/O
R3-
R3-
R3-
NC3
NC3
PSx
Main
Sub
M-SYSTEM WARRANTY
M-System warrants such new M-System product which it manufactures to be free from defects in materials and workmanship during the 36-month period following the date that such
product was originally purchased if such product has been used under normal operating conditions and properly maintained, M-System's sole liability, and purchaser's exclusive remedies,
under this warranty are, at M-System's option, the repair, replacement or refund of the purchase price of any M-System product which is defective under the terms of this warranty. To
submit a claim under this warranty, the purchaser must return, at its expense, the defective M-System product to the below address together with a copy of its original sales invoice.
THIS IS THE ONLY WARRANTY APPLICABLE TO M-SYSTEM PRODUCT AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESS OR IMPLIED, INCLUDING ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. M-SYSTEM SHALL HAVE NO LIABILITY FOR CONSEQUENTIAL, INCIDENTAL OR
SPECIAL DAMAGES OF ANY KIND WHATSOEVER.
M-System Co., Ltd., 5-2-55, Minamitsumori, Nishinari-ku, Osaka 557-0063 JAPAN, Phone: (06) 6659-8201, Fax: (06) 6659-8510, E-mail: info@m-system.co.jp
R3 SUB (RY(n+1) 0)
0
1
0
1
Break
(2)
(3)
Standby
CPU
Master
Master
I/O
R3-
R3-
R3-
NC3
NC3
PSx
Main
Sub
CONTROL
Output from the 'main' network module.
Output from the 'main' network module.
Output from the 'sub' network module.
Hold the output
Restored
(4)
Switching by PLC
(5)
P. 7 / 7
R3-NC3
EM-8422 Rev.9
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