Block use – Rockwell Automation 1757-FFLDC4 FOUNDATION Fieldbus System User Manual User Manual
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Rockwell Automation Publication 1757-UM012A-EN-P - July 2011
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Linking Device Function Blocks Chapter 7
Block Use
One Logix Block lets a Logix controller to send 8 analog outputs and 8 discrete
outputs to H1 devices and to receive 8 analog inputs and 8 discrete inputs from
H1 devices. Each linking device can use up to 16 Logix Blocks.
Within the RSLogix 5000 software, the linking device is configured and each
Logix Block is assigned a slot number, similar to assigning slot numbers to
physical modules. The slot numbers assigned to Logix Blocks in the
RSLogix 5000 software correspond to the slot numbers configured in the Logix
Block in the linking device. The Logix Block in the controller will fail to make a
connection if there is no Logix Block in the linking device configured with a
corresponding slot number.
In RSFieldbus software,
1 VCR = 1 publisher/subscriber (input/output) =
1 Process Variable (PV),
and 1 Logix Block = 1 CIP connection.
A total of 256 publisher and 256 subscriber Virtual Communication
Relationships (VCRs) are possible for a 4-port linking device (128 publisher and
128 subscriber VCRs for a 2-port linking device). This is restricted to 64
publisher and 64 subscriber VCRs per H1 channel.
For information on viewing the actual number of VCRs used on the linking
device’s H1 ports, see the VCR section in the FOUNDATION Fieldbus Design
Considerations Reference Manual, publication
.