GE Fanuc 90-30 series

What kind of protocol is used in GE Fanuc 90-30 series PLC to communicate between master PLC and slave PLC and other I/O racks?

For serial communications, GE Fanuc PLCs can use SNP, RTU, or CCM protocols. For ethernet communications, they can use SRTP, (SNP over ethernet) or Modbus TCP.

They can also use Genius, DeviceNet or Profibus.

This is not an all-inclusive list, just some of the most frequently used. What are you trying to accomplish?

Is it necessary to keep GBC module in PLC master rack , PLC slave rack and other I/O racks to communicate with GBC protocol.

Genius is GE Fanuc's proprietary remote I/O network. A typical network has one Genius bus controller (GBC) and several nodes. The GBC controls all of the outputs connected to the nodes and reads the status of all of the inputs. It is also possible for each of the nodes to know the status of the inputs and outputs from the other nodes, although this is not usually done.

Please post a sketch of the system you have in mind. It will be easier to answer your questions.

If your system is using Series 90-30 bases to house all of your I/O modules, the communication between the base with the CPU module and the rest of the bases is handled by the CPU. You can think of the additional bases as extensions of the CPU base.

If the remote drops in your system have their own CPUs, then communications are handled by the GBCs.

The attached drawing is in my mind.
As the capacity of GBC module is 128 bytes, I guess I need to put one module in each rack.
I will connect all the GBC modules.
Is it necessary to put CPU in drop as well?
How many I/O s GEFANUC CPU 351 and CPU 331 modules can handle?

Are you trying to set up a redundant PLC system?

If your drops are going to be VersaMax I/O, then use a Genius NIU at each drop.

If you want your drops to be 90-30 I/O, then you will need a CPU at each drop. That CPU can be a CPU323 model.

If this is not a redundant PLC, then let the master control the I/O using standard expansion I/O bases and have the master and slave exchange data over the Genius bus. In that case, you won't need GBCs in the drops.

I suggest you look into GE Fanuc's redundancy offerings. Why reinvent the wheel?

Thanks Steve Bailey.
Yes I am trying to setup redundancy PLC system.
I am using 90-30 I/O.As you said if it is 90-30 I/O then one CPU323 to be placed in drop.
The GBC module itself transfer the data to the GBC module in PLC Master rack.
Whay to use another CPU in Drop?
In this setup all the GBC modules are connected each other,Is it Right?
I will try to get the GE Fanuc redundancy offerings.

A 90-30 Genius Bus controller is not capable of stand-alone operation in a 90-30 base. It requires a CPU. That's why you need a CPU in the drops.

You should also rethink your choice of CPU for the master and slave. The CPU331 is old. The CPU350 has more capacity for the same price as the CPU331. The CPU360 has even more capacity. The CPU351 should not even be considered. It can't use the latest firmware.

Thanks a lot Steve Bailey.

Another good option using todays hardware would be to use CPU374s (CPU364 is being replaced by the CPU374 soon) and instead of CPU321s and GBCs on the drops, use ENIUs (Ethernet Network Inerface Units) and standard CPU Racks.
This would use the EGD Protocol (Ethernet Global Data). It is sort of like Genius-over-Ethernet.
It will be faster than Genius and more flexable, but the biggest advantage is this. It is more "modern" so it will not go obsolete as quickly.
I personally believe that Genius, like DataHighway+ is on its way out.

If I use CPU 374 in master and salve racks and ENIUs (Ethernet Network Inerface Units) , do I need to place any CPU in drops ? or only ENIU operates stand-alone.

The ENIU is a "special CPU". It holds only a configuration for the I/O and EGD. So your answer is no, but you do need a CPU rack and put the ENIU in the CPU slot.