We would like to upgrade a large SCADA with main frame server, five micro master units (Intel ICS80MTU) and 33 RTUs. What is the best replacement interms of performance? Replace the MTUs with five servers to act as front end processor or use 10 servers instead, each with fewer PLCs/DCSes at the stations? Which puts more load on the main SCADA servers at the main control room? And how does that relate to the access method used (polling/RBX)? Please help me so I can reach a decision about system architecture.

Adel Abaza, System Analyst
Waha Co.
adelebaza @ yahoo. co. uk

 

Dear,
Problem does not exist in Number of Front End Servers. The Inter-networking may raise Polling/updating or Speed Problem.

If you Choose some Fibre Optic Option with better Telecommunication System for Inter-networking Like SDH supported MUX you may better come up with Tension Less Night Sleeps.

For further clarification You must a bit further clarify your System Layout mentioning Distance Scenerios.

Regards,
Anonymous
Pakistan

 

Thanks for reply, the stations are geographically dispersed and distances range from 10 km to hundreds of kms. The existing network is through company owned Microwave (E1) with multiples of 64k channels that can be dedicated to each station or substation. Some of the stations will be tied with fiber optic soon. We demanded the new system to be based on OPC/ethernet at the local ststions and utilize protocol converters/modems or terminal servers for outbound comuunication links on the Microwave. I hope that helps. If you send me your Email I can send you the existing and proposed system architecture.

Thank you again.

 

If we know the exact location (means distance) I can come up with optimized server count and the exact location to avoid any overloading of any particular server.

Email me... nandakumar.gopal @ gmail. com

Nanda
Sr. Electrical Engg.

 

I would like to see the proposed system architecture diagrams, just for the telemetry usages...

 

Dear Adel,

I would like to suggest the following:

1. Use OPC servers in Station levels for Interfacing IEDs, E.meter, RTUs and PLCs & Server level for interfacing Database & systems.

2. Use GPRS network with fixed IP for linking all RTUs over IEC60870-5-104 or DNP3 for the same. There are many wendors are there to support for GPRS.

3. Share the load with all servers. Once all the RTUs in GPRS network, any server can link to any of the 33 RTUs. So we can share load with Servers easily. Each sever can have seperate Database and a main database server can share all the data with redudancy (with sychronisation).

Regards,

BCG
Amtech Automation
Bangalore, India

 

sorry our WAN is bases on E1 channels that are in multiples of 64K . more than on channel can be used to form up to 1 MBps channels to amaximum of 16M. the bandwidth is limited as this system is used for company voice and data traffic. the limited bandwidth is crucial to our system designh and all channels will be in a ring setup. with the maximum number of chanels dedicated to the central control room where the data will be collected by the main serevers and data historians and client HMI's. Any better ideas?