Omron C200HE User Manual

In looking at the following timing charts, it is important to remember the se-
quence in which processing occurs during the PC scan, particular that inputs will
not produce programmed actions until the program has been executed.

When calculating the response times involving inputs and outputs from another
CPU Unit connected by an I/O Link Unit, the cycle time of the controlling CPU
Unit and the cycle time of the PC to which the I/O Link Unit is mounted must both
be considered.

Noise may increase I/O delays.

The remote I/O transmission time is computed as follows:

T

RM

 = Total Slave transmission time for one Master

= 

Σ

T

RT

 + 

Σ

T

TT

T

RT

  =  Transmission time for each Slave

=  1.4 ms + (0.2 ms 

×

 n)

Where n = number of I/O words on the Slave Rack

T

TT

  =  Optical I/O Unit/I/O Terminal transmission time

= 2 

ms 

×

 m

Where m = number of Optical I/O Units/I/O Terminals

The minimum response time occurs when all signals are processed as soon as
they are received. Here, three scans are required so that the program is
executed, as shown in the following diagram.

Time = Input ON delay + cycle time 

×

 3 + output ON delay

Cycle time > Remote I/O transmission times

Cycle time

CPU Unit

Master

Slave

Input

Output

Program execution

Transfer to CPU Unit

Transfer to Master

Slave I/O refresh