Emerson operation manual Priority Settings, 10-24 E2 RX/BX/CX I&O Manual Rev 4 5-JAN-2013

Status screen.

3.Press  (Setup) to open the Global Data Setup screen.

The Global Data feature is an enhanced method of effectively distributing commonly used input values between multiple E2s. Sensors such as outdoor tempera- ture and outdoor humidity are set up on an E2 as Global Data inputs. This E2 then becomes the “provider” of the global sensor values to all other Global Data applications on the E2.

As a result, a single sensor can be used by any applica- tion in any E2 on the network.

Unless you program it otherwise, the E2 always assumes you will be using Global Data in all your applica- tions. When you create new applications in the E2, it will always automatically connect the appropriate application inputs (except for the spares) to their corresponding Global Data outputs.

10.17.1 Priority Settings

When selecting the priority for a global sensor input, there are four settings to choose from.

Primary Primary inputs are the highest priority inputs. If a sensor is set up with a primary priority, it is recognized by all Global Data applications on the network as the highest priority. The primary provider sends this input value to the other Global Data appli- cations in the other E2s, and each E2 immediately sends that value to all of its own applications that use the Global Data input.

Only one input of each type may be designated as a primary on the E2 Network. In other words, if one E2 is acting as the primary provider of the global Out- door Air Temp, no other E2 on the network may have a global Outdoor Air Temp sensor with a “primary” priority.

If using this priority setting, you must enter board and point settings.

Secondary Sensors that are set up with secondary priorities are backup sensors that will be used by all Global Data applications if the primary sensor fails.

If a global input is set up on an E2 with a secondary priority, the E2 will not send its value to the other Global Data applications as long as it is receiving a primary value of that type from another E2 on the network. If a secondary provider does not receive a primary value update at least once every five min- utes, the secondary provider will assume the primary sensor has failed, and it will send the secondary value to all other Global Data applications on the net- work. These applications will then use the secondary

value in place of the failed primary value.

Secondary providers will continue to send the input value until the primary provider again sends a valid update to the other Global Data applications. The secondary provider would then stop sending the sec- ondary value, and all Global Data applications would use the primary value.

If using this priority setting, you must enter board and point settings.

Example: Out of three E2s, an outside air temperature sensor on E2 A’s I/O Network is set up as the primary provider of the global Outside Air Temp input. A sim- ilar sensor is set up on E2 C with a secondary prior- ity (see Figure 10-45).

As long as E2 A is capable of broadcasting a valid temperature value, all three E2s would use E2 A’s Outside Air Temperature value in their own Global Data applications.

However, if E2 A loses contact with the sensor, E2 A no longer has a valid temperature value to send to the other Global Data applications. After five minutes of no updates from E2 A, E2 C will consider the pri- mary Outside Air Temp source to have failed, and it will begin sending the value of the secondary sensor to the Global Data applications of the other two E2s. All E2s would then use this secondary value as Out- side Air Temperature.

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