Kontron CP383 - Manual (Page 73)

CP383 System Considerations
ID 27784, Rev. 01 © 2004 Kontron Modular Computers GmbH Page 6 - 3
27784
.01.VC.040308/162549
P R E L I M I N A R Y
6. System Considerations
6.1 Introduction
In addition to the basic specification requirements for the CP383 which have been addressed
in chapter 4, system integrators need to be aware of the overall system environment and the
application needs when designing the interfacing to the CP383. The following chapters address
a number of more apparent considerations which should be addressed, but certainly not all of
the possible situations which may be encountered. Many of the considerations presented here
are recommendations, but some are definite requirements if the CP383 is to successfully
achieve its purpose.
6.2 General
Considerations:
1. Care must be taken to ensure that proper grounding concepts are followed, and that the
integrity of the grounding system within the application be maintained.
2. Input wire routing should avoid proximity to high voltage or current sources.
3. Where possible input wiring length should be kept as short as possible.
6.3 Shielding
Considerations:
1. Input cable shielding in general is recommended.
2. The requirements for shielding can be seen primarily as a function of the system design
and environment, but empirical results must also be considered.
3. The CON2 connector has a metal housing which is connected to the CP383 shield and
is isolated from the system ground.
4. Ensure that if shielding is used that it is not in anyway connected to the system ground.
6.4 Debouncing for Digital Inputs
On the CP383 it is possible to select from a number of debouncing times, dependant on the
type of switches/sensors in use. For example, when using mechanical switches or relays to
switch the input, bouncing will always occur and therefore debouncing is necessary. A de-
bounce period may be selected from a range of values available, accessible via software in the
register depending on the settle time. Where it is known that an application does not generate
bouncing problems, the debounce period may be set to the default value.