ABB S800, Product Manual

Page: 145 / 186

Section 3 Technical Data and Performance Calculation of Maximum Distance of an Optical
3BSE015969-600 A 145
Calculation of Maximum Fiber length for TB826
The maximum signal delay in a configuration is calculated using Optical Media
Converter. This is calculated using the signal path from the controller to the point in
the configuration that has the longest delay. The maximum delay in a optical
ModuleBus configuration must be

100
µ
s (less than 250
µ
s for

S800 I/O HI).

The delay values in Table 30 can be used to calculate the maximum delay in an
optical ModuleBus configuration.
Table 30. Delay Values Optical ModuleBus Components
Opto-to-opto delay in TB826
(1)
(1) Notice that the delays in the table is the sum of the communication delay in both directions, i.e.
(delay of master frame) + (delay of slave frame).
2.0 µs
Opto-to-opto delay in TB820
(1)
4.0 µs
Opto-to-electrical delay in TB820
(1)
6.5 µs
Opto-to-opto delay in TB840
(1)
2.0 µs
Opto-to-electrical delay in TB840
(1)
5.5 µs
Delay in optical fiber
(1)(2)
(2) Total fiber length = total local fiber field fiber length
(0.01 x length) µs