Kontron CP371 - Manual (Page 59)

CP371 System Considerations
ID 23762, Rev. 02 © 2002 PEP Modular Computers GmbH Page 5 - 3
5. System Considerations
5.1 Introduction
In addition to the basic specification requirements for signals being presented to the CP371
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 CP371.
There are certain basic considerations which require explicit resolution as well as others which
are of a more subtle nature that may under circumstances impact the performance or validity
of the analog to digital conversion process. The following chapters address a number of more
apparent considerations which should be addressed but certainly not all of the possible situa-
tions which may be encountered. Many of the considerations presented here are recommen-
dations, but some are definite requirements if the CP371 is to successfully achieve its purpose.
5.2 General
Considerations:
1. All unused input channels must have their pins tied to analog ground.
2. For input channels in use, the
I pin is not connected except when required.
3. Distribute analog ground connections over all the available CON2 analog ground pins.
Don’t just use one or two pins.
4. It is recommended to use twisted pair wiring for input signals.
5. Mixing of input signal types (single-ended, differential, and current) presented to the
CP371 is permitted.
6. The type of signal presented to each input channel the CP371 must correspond to the
driver software configuration for that channel. If not the result will be erroneous and the
CP371 may be damaged.
7. 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.
8. Input wire routing should avoid proximity to high voltage or current sources.
9. Where possible input wiring length should be kept as short as possible.
5.3 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 CP371 shield and
is isolated from the analog ground.
4. Ensure that if shielding is used that it is not in anyway connected to the analog ground.