Goals and Symptoms

How to Split a system from single IO Server into Multiple IO Servers in PowerScada Expert

Causes and Fixes

The following are the steps involved in migrating a system with a single IO server to multiple IO server on a redundant system. Similar steps can be followed for a standalone system, ignoring the redundancy part.
For this example, the system is a single Cluster, with a single Alarm server, Trend server, and multiple IO Servers running in PLSCADA hot standby.

Step 1. Decide how many IO Servers to split into. This depends on how many available CPU cores the system have, and how large the system is. The multiple IO servers work best when each IO server is assigned to a separate CPU core. In PLSCADA 7.2, there have been issues with putting more than 100 Micrologic breakers on one IO server. This effectively equates to around 400 individual modbus devices. Putting 50-75 Micrologics on one IO server will yield a startup time of around 5 minutes for that server. CM4000s and other fast communicating devices can handle more on one IO server.

Step2. Create the individual IO servers. This can be done directly in the Project Editor. Please note that every IO server must have a unique IP address OR unique TCP port. By default (leave blank), the IO server uses port 2082. You can arbitrarily assign ports for the new IO servers, such as 2083,2084,12082,12083,etc. Be sure the port is unused on the network. If this system is part of another network, be sure the switch/firewall is not blocking the ports otherwise special rules must be programmed by IT. The IO servers must have unique names and must be mirrored between primary and secondary. This means if you have 5 on primary, you should also have 5 on secondary.

Step 3. Create the appropriate ports and board for each IO Server. This must be done directly in the DBF of the system. Please note that every entry is doubled because of the primary/standby feature. Make sure when adding entries, you copy the entire row and not just the values you see as there might be more attributes to the right of the screen.

Boards This is the only place in the DBF that you will ADD entries:

The Names do not have to be Unique, but whatever the name is, it must match in the IO Devices.

Step 3.1. In Ports, assign each individual port to the desired IO server, keeping track of what each IO server/Port is since this same change must be done to the devices. The double entries are for the redundancy.

Step 4. Go to IO Devices , and assign the appropriate IO Server to the devices. It is important to keep ALL devices on one port tied to the same IO Server. Example, if there is a chain of Micrologic on PORT1, IOServer3 primary, IOServer4 Secondary, then ALL of those devices must share the same IO server. The double entries are for the redundancy.

Step 5. Pack and compile the project. There should not be any errors if the splitting was done correctly.

Step 6. Run the computer setup wizard and assign each IO server to a different CPU core. PLSCADA can only support up to 32 CPU Cores (CPU 0-31) even if the server has more than that.