System Performance

Memory Consumption

Input and output memory specification for I/O data:

Scope	Type	Maximum Value per Scan1
Scope	Type	BMEH582040(S)	BMEH584040(S)	BMEH586040(S)
M580 Hot Standby CPU	input bytes per network	16384 bytes2	24576 bytes3	24576 bytes 3
M580 Hot Standby CPU	output bytes per network	16384 bytes2	24576 bytes3	24576 bytes 3
Ethernet RIO	input words per drop	1400
Ethernet RIO	output words per drop	1400
Ethernet DIO	input bytes per device	up to 1400, depending on EtherNet/IP or Modbus/TCP function code
Ethernet DIO	output bytes per device	1400
Total DIO scanning capability	input (KB)	up to 2
Total DIO scanning capability	output (KB)	up to 2
1. Hot Standby supports the MAST, FAST, and SAFE tasks. AUX0 and AUX1 are not supported. 2. Of the total amount, up to 3072 bytes can be FAST task data. 3. Of the total amount, up to 5120 bytes can be FAST task data.

Displaying I/O Memory Consumption

You can monitor the I/O memory consumption in Control Expert. Use one of these methods:

In the Project Browser, expand Project → Configuration → EIO Bus. Right-click Properties.

— or —
In the background of the EIO Bus window, right-click Bus properties.

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In the Edit menu, select Bus properties.

Exceeding RIO Drop Limitations

Control Expert detects an error and displays it in the log if one of these events occurs:

The size of the RIO drop memory for the MAST task exceeds 1,400 input bytes or 1,400 output bytes.
The size of the RIO drop memory for the FAST task exceeds 1,400 input bytes or 1,400 output bytes.
The size of the M580 network exceeds 80% of the maximum drop limit for the selected CPU.

Minimum / Maximum System Channels

The minimum and maximum number of channels that a global M580 configuration can manage is a function of the M580 CPU model that you are using. For detailed information on configuring channels, refer to the Modicon M580 Hardware Reference Manual.