Introduction

A local rack in an M580 system contains one CPU from the BME P58 family. Use this table to select a CPU for your system:

 

BME P58 •0•0 CPU Reference

Communication Capability

1020

2020

2040

3020

3040

4020

4040

5040

6040

maximum number of RIO drops

–

–

8

–

16

–

16

31

31

maximum number of local racks (main rack + extended rack)

4

4

4

8

8

8

8

8

8

maximum number of communication modules on the local rack(1)

2

2

2

3

3

4(3)

4(3)

4(3)

6(3)

Ethernet I/O scanner service

DIO

DIO

RIO, DIO

DIO

RIO, DIO

DIO

RIO, DIO

RIO, DIO

RIO, DIO

maximum number of distributed devices managed by a CPU with Ethernet I/O scanner service(2)

64

128

64

128

64

128

64

64

64

maximum number of discrete I/O channels

1024

2048

2048

3072

3072

4096

4096

5120

6144

maximum number of analog I/O channels

256

512

512

768

768

1024

1024

1280

1536

– not available

(1) includes BMENOC0301/11, BMXEIA0100, BMXNOR0200, and BMXNOM0200 communication modules

(2) includes three slots for local slave functionality

(3) Only three of these modules can by BMENOC0301/11 modules.

NOTE:

  • M580 CPUs have three Ethernet ports. The top port is the service port.

  • A device network contains both RIO modules and distributed equipment.

CPU Processing Capacity

Use this table to compare for each station the total number of messages received via the Modbus message service if used (values R1, R2, or Ri) with the capacity of the station CPU.

Processing of Modbus requests per PAC scan cycle:

CPU Module

Messages Received

BMEP581020

16 messages/cycle

BMEP582020

24 messages/cycle

BMEP582040

24 messages/cycle

BMEP583020

32 messages/cycle

BMEP583040

32 messages/cycle

BMEP584020, BMEP584040, BMEH584040.

40 messages/cycle

BMEP585040

48 messages/cycle

BMEP586040, BMEH586040.

64 messages/cycle

The above table shows the maximum number of requests per cycle. The internal communucation port that sends the request can limit this maximum:

  • USB: maximum of 4 requests

  • X Bus: maximum of 16 requests

  • Ethernet ports: maximum of 32 requests (including backplane ports and copper ports on the front of the module)

NOTE: Messages per cycle represents the number of messages received per cycle from the PAC master task (typical cycle of 50 to 100 ms).

Ethernet Transaction Processing Capacity

Use this table to compare for each station the total number of messages received (values Ri or Rj) and the total number of messages transmitted (values Ei or Ej) (for example, station N).

Use the elements below for the Ethernet connection per PAC, rather than the number of transactions required by the application:

CPU Module

Ethernet Transaction Processing Capacity

Value

BMEP581020

BMEP582020

BMEP582040

BMEP583020

BMEP583040

BMEP584020

BMEP584040

BMEP585040

BMEP586040

BMEH582040

BMEH584040

BMEH586040

Modbus messaging

500 transactions/s

I/O scanning service

7,500 transactions/s

Simultaneous TCP/IP Connections

The number of simultaneous TCP/IP connections depends on the type of connection to the Ethernet network:

  • 10/100BASE-TX network module port

  • 10/100BASE-TX embedded CPU port

This table show the number of simultaneous TCP/IP connections that are available for Ethernet communication modules and CPU modules:

 

Ethernet Module

CPU

BMENOC0301/11

BMEP581020

BMEP582020

BMEP582040

BMEH582040

BMEP583020

BMEP583040

BMEP584020

BMEP584040

BMEH584040

BMEP585040

BMEP586040

BMEH586040

client

16

16

32

48

80

80

server

32

64

96