Rockwell-automation Logix5000 Controllers Produced and Consumed Tags P Instrukcja Użytkownika Pobierz pdf (Strona 18)

Chapter 1 Produce and Consume a Tag

If the PLC-5C controller consumes REALs,

reconstruct the values.

When you produce REALs (32-bit floating-point values) for a PLC-5C controller, the PLC-5C controller stores the data in consecutive

16-bit integers.

• The first integer contains the upper (leftmost) bits of the value.

• The second integer contains the lower (rightmost) bits of the value.

This pattern continues for each floating-point value.

If the PLC-5C controller consumes REALs,

reconstruct the values.

When you produce REALs (32-bit floating-point values) for a PLC-5C controller, the PLC-5C controller stores the data in consecutive

16-bit integers.

• The first integer contains the upper (leftmost) bits of the value.

• The second integer contains the lower (rightmost) bits of the value.

This pattern continues for each floating-point value.

The following example shows how to reconstruct a REAL (floating-point value) in

the PLC-5C controller.

Example:

Reconstruct a floating point value.

The two MOV instructions reverse the order of the integers as the integers move to a new location.

Because the destination of the COP instruction is a floating-point address, it takes two consecutive

integers, for a total of 32 bits, and converts them to a single floating-point value.

Controllers can be programmed to enhance the requested packet interval (RPI)

acceptance between producing and consuming tags within specified limitations

for multicast connections using version 18 and later of the application. A

producing controller verifies that the RPI of incoming connections are within the

produced tag settings. If the consuming tag’s RPI falls outside the configured

range, a producing controller will reject the incoming RPI and may provide an RPI

(default) to the consuming controller.

This optional default RPI applies only if the consuming controller is set up to

allow its consumed tags to use an RPI provided by the producer. You can choose

to not use the default value. However, you will have to manually change a rejected

RPI to make the value within the limitation settings for the produced tag.

Important:

1769-L2x and 1769-L3x controllers have additional RPI information. See

1769-L2x and 1769-L3x

RPI limits on page 28 for details.

RPI limitations and

negotiated default

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Rockwell-automation Logix5000 Controllers Produced and Consumed Tags P Instrukcja Użytkownika Strona 18