Within range
Read input value converted into User Range
0 a 20 mA
Signal disconnected
4 a 20 mA
0 mA converted into User Range
----
w i l l be displayed
-22000 will be logged in the memory
Slightly above the upper limit
Read input value converted into User Range
*
Current
0 to 20 mA
4 to 20 mA
0 a 20 mA
Slightly below the lower limit
4 a 20 mA
It is not possible to decrease more than
the lower limit
Read input value converted into User
Range *
Far above the upper limit
Vvvv
will be displayed
32767 will be logged in the memory
0 a 20 mA
Far below the lower limit
4 a 20 mA
It is not possible to decrease more than
the lower limit
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 02
– Measurement and indication of input types by
LogBox BLE
LogBox BLE
allows
you to configure settings to be applied to analog sensor readings. These settings can be used to correct sensor or process
errors in which the sensor is installed and can be applied indi
vidually for each analog channel. Two adjustment modes are provided by the device:
•
Offset
: It allows f
or 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.
•
Custo
m Calibration
: It is a feature that allows you to e
nter up to 10 set points for each channel in order 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 the error at those points. 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 is optional, only available for those who wish to
adjust the indication to a local standard, since the
LogBox BLE
is already fully factory calibrated.
When
ever you change the input type, make sure that the custom calibration points of the previous input are deleted!
For each analog cha
nnel, a unique tag 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: when using temperature sensors
(Pt100 or thermocou
ples) you must choose between Celsius (°C) and Fahrenheit (°F) degrees; when using 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 BLE
working
range for the chosen input type). Example: the input type 4
to 20 mA is selected and a pressure transmitter from 0 to 2 bars is 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 using any device on the analog inputs that are connected to the mains (e.g., thermocouple or voltage simulator), and it is not isol
ated, it is
re
commended to use a different reading interface than USB. In some cases, noise and read offsets have already been detected due to the
in
fluence of the USB cable connection, probably by ground loops.
The
LogBox BLE
, when operated by batteries, keeps the
entire analog circuit switched off while no acquisition is being made. This strategy is
necessary so that it c
an operate for more than 2 years without needing to change batteries. This characteristic may cause some undesirable effects
during calibration, as
some analog signal simulators (e.g., thermocouple simulator, Pt100) may not operate properly, causing false reading offsets
and oscillations. If su
ch a problem is identified, it is recommended to power the
LogBox BLE
via external power supply or USB while using the
simulator.
It is important to set the local network frequency (50 Hz or 6
0 Hz) to improve the reading performance of the analog channels, even if the device is
running on batteries. The power grid typically causes interference in the signal read from the sensors, which can be more easily mitigat
ed if we
know the frequency.
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