User manual

Analog I/O expansion module Berghof Automationstechnik
16 2D0172002ZD00.DOC 2VF100051FE01.doc
2.7. Operation of the module
Warning !
Do not insert, apply, detach or touch connections when in operation!
Destruction or malfunctioning may otherwise occur. Disconnect all incoming sup-
plies before working on modules, including those of connected peripherals such as
externally supplied sensors, programming devices, etc.
The module is designed for measuring and control functions located on a common
potential island.
Items of equipment on differing potential levels can be connected via suitable isola-
tion devices (insulating amplifier etc.).
Note:
The module electronics power supply (connection voltage +24V
DC
) is not electri-
cally isolated from the analog connections on the module. The negative connec-
tion point for the incoming supply (M1) is physically connected to the analog earth
connection (AGND).
We recommend that all sensors/actuators be operated on this supply together with
the module.
Consciously arranging analog wiring with a common earth is good practice.
The module is designed to cope reliably and effectively with the small differences
of potential unavoidably occurring when sensors and actuators are supplied jointly
through appropriate SENSE lines.
Caution
The module’s analog channels may be connected to different earths only within
the permissible common mode range.
More extensive electrical isolation is not permissible for design reasons.
Non-compliance with the above will cause incorrect measurements, even on unin-
volved channels, and can result in transient currents which will cause permanent
damage to the module.