DESIGNER’S HANDBOOK 4189350049C EN
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If there are more analogue or digital inputs in a system than one XDi can handle, it is possible to make several XDi
units with extension modules work together providing all data on CAN for the rest of the indicators to use. This is
made very easily when the XDi-net protocol is used, but can also be achieved using TPDO/RPDO data sharing.
Please note, that normally only input data used by the selected virtual indicator is shared on the CAN bus. In
customised libraries, it is possible to make an extra invisible input to share a data type that is not used by the virtual
indicator itself, but only shared on CAN.
5.6
AX1 analogue extension module
The AX1 analogue extension module contains two analogue standard inputs (1 and 2). Each can be configured as
voltage (high or low voltage), current (high or low current) or potentiometer input.
In addition, a 3
rd
voltage input is intended as input for an analogue dimming voltage (range +/-30 V). This input is
fully calibrated and may also be used as an extra indicator input (voltage or potentiometer).
The XDi supports up to 7-point calibration of an un-linear analogue input, normally 2-
point is used of 0…X type
data and 3-point for
–X…0…X data types.
The number of calibration points is predefined in the selected VS profile and cannot be changed via the input adjust
menu.
It is possible to adjust key parameters for the analogue input via the XDi menu. This can be used to align the input
and scale max/min input correct.
5.6.1
Reference voltage for potentiometer applications
The AX1 module has a very stable reference voltage 7.3 V DC (7-7.5 V) with a built-in voltage monitor
function. This is intended for potentiometer applications, since the variations in the reference voltage will be
measured and automatically compensated to obtain a very high accuracy. It is even possible to overwrite the
reference voltage output by an external voltage between 7.5 V to 30 V DC still monitored and variations are
compensated.
5.6.1.1 Advanced potentiometer load correction
When a potentiometer is used as voltage source, the internal resistance of the analogue input circuit will load the
potentiometer output resulting in a measuring error. The load impact depends of the resistance value of the
potentiometer that is used. If the potentiometer has a low resistance the impact is low, but the higher the
potentiometer resistance is, the more impact the load will have on the measurement.
When the high voltage input type is used it possible to enable a potentiometer compensation function in XDi. It can
be activated and setup in the VS profile, but it can also be activated and setup in the input adjust menu. When this
function is activated with the correct potentiometer resistance value inserted in
Ω, then XDi will compensate for the
error caused by the load of its own analogue input resistance (112 k
Ω).
The benefit of using this function is most significant for linear potentiometers with high resistance.
Please note:
This function is only available on single high voltage inputs (HV1, HV2 or HV3), not for double input
configuration like SIN/COS or Double triangle potentiometers for example used for 360° angle measurements.
Due to the nature of those dual input types, the load impact is much lower and insignificant for potentiometer values
up to at least 5 k
Ω.
5.6.2
Analogue input types
The setup and scaling of the analogue indicator inputs are predefined in the selected VI-setup profile (VS).
If input 3 is used as dimmer input, the default setup parameters are defined in the selected product profile (PP).
The analogue input types are shown below. Select the input type and value that best fits your application.
