Rockwell-automation 1771-SPI,D17716.5.122 SPI PROTOCOL INTERFACE Instrukcja Użytkownika Pobierz pdf (Strona 12)

Overview of an SPI Communication Network

Chapter 1

1-6

The SPI module can store the configuration blocks of:

up to 10 different types of devices (device types) such as mold

temperature controller, hot runner, and/or dryer controller

no more than one device (of a given device type) at a time

(for example, only one mold temperature controller)

unless they are identical with respect to:

- configuration, data, and status blocks

- command bits, such as for turning the device on or off

- presets, such as setpoints and alarm limits

- status bits and words

Exception : If you must network to different devices of the same type

(mold temperature controllers (MTCs) from different manufacturers),

then your program may become very complex because it must:

a. clear the previous configuration and data blocks

(for the MTC from company A)

b. replace them with a new set of configuration and data blocks

(for the MTC from company B)

c. communicate with the device from company B

d. repeat the three steps for each different device of the same type

(for the MTCs from companies C, D, etc.)

How

Many Different Devices

Can the SPI Network

Handle?

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Rockwell-automation 1771-SPI,D17716.5.122 SPI PROTOCOL INTERFACE Instrukcja Użytkownika Strona 12