NOVUS AUTOMATION
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INPUT TYPE
INPUT SIGNAL CONDITION
INDICATION
Far below the lower limit
nnnn
will be displayed
-32000 will be logged in the memory
Current
0 to 20 mA
4 to 20 mA
Within range
Read input value converted into User Range
Signal disconnected
0 a 20 mA
0 mA converted into User Range
4 a 20 mA
----
will be displayed
-22000 will be logged in the memory
Slightly above the upper limit
Read input value converted into User Range
*
Slightly below the lower limit
0 a 20 mA
It is not possible to decrease more than
the lower limit
4 a 20 mA
Read input value converted into User
Range *
Far above the upper limit
Vvvv
will be displayed
32767 will be logged in the memory
Far below the lower limit
0 a 20 mA
It is not possible to decrease more than
the lower limit
4 a 20 mA
nnnn
will be displayed
-32000 will be logged in the memory
(*) Note
: The analog channel indication continues slightly beyond the limits specified for the selected input type. However, in this condition, accuracy is not guaranteed.
Table 2 –
Measurement and indication of input types by
LogBox Wi-Fi
LogBox Wi-Fi
allows you to configure settings to be applied to analog sensor readings. These settings can be used to correct errors in the sensor
or process in which the sensor is installed and applied individually for each analog channel. Two adjustment modes are provided by the device:
•
Offset
: Allows each analog channel to choose an Offset value to be added to the channel reading indication. It is a simple and fast feature to
adjust the display throughout the range.
•
Custom Calibration
: Allows you to enter up to 10 set points for each channel to correct distortions in reading these channels at these points.
We call this characteristic a "custom calibration" because it allows the user to adjust the indication at the desired points by zeroing their errors.
The adjustment is made linearly between the points entered, according to the values entered.
It is important to note that both the Offset adjustment and the insertion of custom calibration points are optional, only indicated for those who wish to
adjust the indication to a local standard, since the
LogBox Wi-Fi
has already been calibrated at the factory.
Whenever you change the input type, make sure that the custom calibration points of the previous input are deleted!
For each analog channel, a unique (Tag) name must be assigned, which will be used to reference the channel. You should also choose the type of
input (sensor) that will be connected to that channel. In addition to that, you can assign the unit of measured value: for temperature sensors (Pt100
or thermocouples), degrees Celsius (°C) or Fahrenheit (°F); for linear sensors (current or voltage), you can enter the desired unit.
In the case of linear input types, one must choose the sensor indication range, that is, what the channel should indicate when the input is at its
minimum value and what it should indicate when it is at its maximum value (minimum and maximum values considering the
LogBox Wi-Fi
working
range for the chosen input type). Once the 4 to 20 mA input type is chosen, for example, a pressure transmitter from 0 to 2 bars will be connected.
In this case, "0.0" must be chosen as the minimum value and "2.0" as the maximum value in the input configuration. All resolution and accuracy
available will be contained within the chosen range.
When a simulator is used on analog inputs that are connected to the mains (e.g. a thermocouple or voltage simulator) and it is not isolated, it is
recommended to use a different reading interface than USB. In some cases, the occurrence of noise and read Offset
s
has already been detected
due to the influence of the USB cable connection, probably by ground loops.
LogBox Wi-Fi
, when operated by batteries, keeps the entire analog circuit switched off while no acquisition is being made. This strategy is
necessary so that it can operate for more than two years without needing to change batteries. This characteristic may cause some undesirable
effects during calibration, as some analog signal simulators (e.g., thermocouples simulator or a Pt100) may not operate properly, causing false
reading Offset
s
and oscillations. Should such a problem be identified, it is recommended to power the
LogBox Wi-Fi
by external source or USB
cable while using a simulator.
Setting the local network frequency (50 Hz or 60 Hz) is important as it helps improve the performance of reading analog channels even while the
device is running on battery power. Usually, the power grid causes interference in the signal read from the sensors, which can be more easily
mitigated if we know the frequency.
