Program compatibility constraints

This API supports the scenarios described in the previous section with an important restriction: The service point program must always be able to accommodate the meter program. For example, if you make a change to an existing meter program, you must look at the existing service point program to verify that the service point program supports the change to the meter program. If it does not, you must change the service point program to support the change made to the meter program. These two programs must complement each other.

This constraint exists because IEE stores and performs validation and estimation on metered data at the service point channel level. This is the link between the physical part of the data model and the business side of the data model. The service point program is allowed to define channels for which there is no metered channel available, but the reverse case is never allowed.

A helpful analogy is the ability for a two-pronged electrical plug to fit in a three-pronged socket. The reverse case is impossible.

The following illustration shows a non-metering example of a compatibility constraint:

Photo of an electrical socket.

Photo of a three prong electrical plug.

Image of a two prong electrical plug.

This electrical socket represents a service point program that's able to accept 3 channels of metered data.

This  3-prong electrical plug represents a meter program that fits into the Service Point socket with all 3 channels linking up to each other.

This 2-prong electrical plug represents a 2-channel meter program. This meter program  fits into a service point channel program that has 3 channels. One of the service point channels is left open and holds no data. This is allowed.

The following illustration shows a restricted case, where there is a metered channel that can't plug into a service point channel:

Image of a three prong electrical plug.

Photo pf an electrical socket.

This 3-prong electrical plug represents a 3-channel meter program.

IEE doesn't allow a 3-channel meter program to link to  a 2-channel service point program.

A 2-channel service point can accept either two 1-channel meters, or one 2-channel meter. If the meter program has a third channel, the service point program has nowhere to plug the channel into.