Rpi limitations and negotiated default – Rockwell Automation Logix5000 Controllers Produced and Consumed Tags Programming Manual User Manual
Page 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
for details.
RPI limitations and
negotiated default
18
Rockwell Automation Publication 1756-PM011F-EN-P - October 2014