Emerson ROC827 instruction manual Tuning the Configuration

ROC827 Instruction Manual

3.2.1 Tuning the Configuration

The PM-12 Power Input module can supply a maximum of 36 W (36000 mW) to the backplane, which includes the +T overhead. The PM-24, when operating between –40°C to 55°C, can supply a maximum of 30 W (30000 mW) to the backplane. Across its entire operating range (–40°C to 85°C) the PM-24 can supply 24 W (24000 mW).

Refer to Table 3-5 and the value you entered in the Total for ROC827 Base Unit and All Modules line. That is the value against which you “tune” your configuration to accommodate your Power Input module. If your configuration requires more power than the Power Input module you intend to use, you need to modify your I/O module configuration to reduce your power requirements.

Tuning Hints Review the content of Tables 3-6 through 3-15. Suggestions to help you better align the configuration of your ROC827 with the capability of the Power Input module you intend to use include:

ƒReduce the +T usage by providing an external power supply for as many transmitters or field devices needed to reduce the value in the Total for ROC827 Base Unit and All Modules line on Table 3-5 to below the capability of the Power Input module you intend to use.

ƒReduce the +T usage by reducing the number of transmitters or field devices.

ƒReduce the total number of I/O modules by consolidating transmitters or field devices onto as few I/O modules as possible.

Note: Tuning your I/O module configuration may require several iterations to rework the content of Tables 3-6 through 3-15 until your power requirements match the capability of the Power Input module you intend to use.

Issued Mar-06 Power Connections 3-11