Components and System

Components Performances

The following table sums up components performance in a time stamping solution:

Topic	Device	Value
Time stamp resolution (between 2 identical source modules)	BMX ERT 1604 T	2 < time stamp resolution < 4 ms (with the same time source)
	BMX CRA 312 10	10 ms
	140 ERT 854 20	1.5 ms
Time stamp resolution (in the same source module)	BMX ERT 1604 T	1 ms
	BMX CRA 312 10	1 cycle time (< 10 ms)
	140 ERT 854 •0	1 ms
Maximum number of I/O and available memory ^(1.)	BMX ERT 1604 T	16 discrete inputs on the module
	BMX ERT 1604 T	255 events in internal buffer
	BMX CRA 312 10	256 discrete I/O configured
	BMX CRA 312 10	4000 events in internal buffer
	140 ERT 854 •0	32 discrete inputs on the module
	140 ERT 854 •0	4096 events in internal buffer
1. The maximum value depends on the global system performance, it is not an absolute value and must be balanced.

System Limitations

The following table sums up system limitations in a time stamping solution:

Topic	Description	Value
Maximum amount of devices in an Ethernet remote I/O drop	BMX CRA 312 10	1 per drop
	BMX ERT 1604 T	9 per drop ^(1.)
	140 ERT 854 •0	No limitation ^(2.)
Maximum amount of devices in the system	BMX CRA 312 10	31 in the system
Maximum amount of devices in the system	BMX ERT 1604 T	25 in the system
Maximum amount of sources of events polled	Maximum discrete I/Os per PLC (Modicon M340 local drop or Quantum PLC)	2500
Maximum amount of discrete inputs (and outputs) monitored by the PLC for all the time stamping modules	For all the BMX ERT 1604 T	400 discrete inputs ^(3.)
	For all the BMX CRA 312 10	2048 discrete I/O ^(3.)
Maximum number of events per reading request	For a BMX ERT 1604 T EFB request	20
Minimum timeout setting between reading requests	Between BMX ERT 1604 T EFB requests	5 ms
1. A BMX ERT 1604 T module contains 4 expert channels. A Modicon X80 drop supports a maximum of 36 expert channels, so it supports a maximum of 9 x BMX ERT 1604 T modules if there is no BMX EHC 0•00 counting module in the drop. 2. In a Quantum S908 remote I/O architecture, 9 x 140 ERT 854 10 and 8 x 140 ERT 854 20 modules per drop. 3. The maximum value depends on the global system performance, it is not an absolute value and must be balanced.