|
MELSEC-Q series redundancy CPU is put on the market, half a year passes, it is adopted, and it has come to be seen. QnPRHCPU became a type of connecting two systems with quite the same unit composition with the tracking cable and reduplicating though was Q4ARCPU that the power supply and CPU and the communication unit symmetrically arranged in one base until a few years ago.
|
Commentor / R.Takeuchi |
| |
MELSEC-Q Series Redundancy CPU System |
It was necessary to drop the power supply when units that due to the breakdown of the base when there was a couple of Redundancy system on one base the possibility of the system down, and broke down were exchanged, to change the unit or to change it by using the online detaching function. When the breakdown occurs, it is possible to maintain it easily because all of the standby system system can be wholly changed for this in MELSEC-Q Redundancy system.
Time will increase in the redundancy system of MELSEC-Q series to the extent that the program for remote I/O is written when a common unit should use as a remote I/O station of MELSECNET/H, and uses a special unit though a special unit and the I/O unit can be arranged in the increase base so far, and were able to be used as a common unit of both factions CPU.
Writing operation of parameter program of both systems to CPU
The developer doesn't consider Redundancy CPU and the program development can be done because it is written in Standby CPU being first written in the memory of Control CPU when "Writing" operation is executed from the GX developer, and continuously.
A system automatically becomes a control system when CPU is done in RUN, B system becomes a standby system, and operation begins.
Redundancy Parameter
In the project of the redundancy system, some Redundancy parameters exist.
Because the tracking of all devices is effective in default, the correspondence can be kept complete by system CPU A and system CPU B.
It is also possible to specify the range of the device and the kind the tracking.
|
There is Redundancy setting also in the parameter of Ethernet, and station number and IP address of B system can be specified here.
Moreover, when the communication trouble is occured in a specified port, it is possible to change to the setting automatically switched to the standby system.
It automatically switches into the standby system when the communication error occurs in port 1 of the UDP/MC protocol if it sets it as shown in a left chart.
|
Ethernet communication from PC system
Because system CPU A and system CPU B always reach the same device value if all devices are done in the tracking as operation when it is normal, the same value even if it accesses CPU A or CPU B, is obtained.
However, the control switches into system CPU B, if the power supply of A system is downed. It is neccessary that the communication of a PC system automatically switches into B system, too is caused in CPU of A system because it has already become inaccessible.
The user need not to consider the switch of the communication system in case of correspondence to MELSEC-Q redundancy system. If not so, you have to manually switch to access CPU B.
For example, as the control continues operating like A system in the case where it is assumed that the redundancy system was used like the default setting, and a pertinent port of HUB that the Ethernet unit of the control system connects breaks down, it needs to access the device memory of system CPU A through system CPU B.
It accesses CPU of A system if it is "SM1515=1", and if it is "SM1515=0", the mechanism is needed to access in CPU of B system. As an external system can be generally judged A system operates or B system operates as a control system by referring to the special register of "SM1515" generally.
It does to the redundancy system for acceptnace of complete, and when the redundancy system is introduced, I think our communication software DeviceXPlorer OPC server for it to be able to examine it by all means because it comes to be able to use it without considering the above mentioned thing.
|
|
Inside MELSEC
Advanced OPC