PiXtend eIO Hardware Manual
Connection Notes
The following diagram illustrates the connection of consumers and devices to the analog
current outputs of PiXtend eIO Analog One.
If the outputs are connected with analog inputs of other control units, power amplifiers
(also frequency converter) or similar, the ground connections (GNDs) of the devices and
PiXtend eIO must also be connected. A GND connection can be found on the terminal
block between the analog outputs and inputs. In addition, there are two GND connections
directly next to the power outputs.
As with analog inputs
, shielded cables should be used for analog output lines.
The overload detection (also called "AO-OL" - "analog output overload") monitors the
current flow from the outputs. Each of the two channels is monitored separately and can
pass on an overload message to the bus master. For further details of the evaluation in the
software, please take a look at the software manual of PiXtend eIO.
Already in the quiescent state of the current output (output value 0.0 mA), a wire break or
the absence of a correct wiring can be detected. With the output of 20 mA the overload
detection starts from a load of 500 Ω. This value should not exceed a correctly designed
signal path with sensor and cables.
Reliable operation is still guaranteed up to a burden of 600 Ω.
The six blue potentiometers on PiXtend eIO Analog One are used during production for
8
The cable screen is, however, applied as near as possible to the remote station.
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Figure 47: Principle circuit diagram: connection of the analog current outputs
