NOVUS AUTOMATION
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INPUT TYPE
CONDITION OF INPUT SIGNAL
INDICATION
Current (mA):
4 to 20 mA
and 0 to 20 mA
Within the range
Value read from input
Disconnected signal
4 a 20 mA: Value of configured error
0 to 20 mA: 0 mA
Just above the upper limit
Value read from input *
A little below the lower limit
4 to 20 mA: Value read from input *
0 to 20 mA: it is not possible to
decrease besides the inferior limit
Far above the upper limit
Value of configured error
Far below the lower limit
4 to 20 mA: Value of configured error
0 to 20 mA: it is not possible to
decrease besides the inferior limit
(*) Note:
The indication of the analog channel is still a bit beyond the limits specified for the selected input type. However, in this condition, the
accuracy is not guaranteed.
Table 01
- Measurement and indication of the
FieldLogger
input types
For each channel, you have to choose the digital filter to be used in this channel reading, with valid values between "0"
(no filter) and "20" (maximum filter): the higher the value of the filter is, the lower are there fluctuations read in the input,
but the slower is the channel response to changes in the input signal.
There is also the feature of inserting up to 10 points for each channel in order to correct distortions in the reading of
these channels at these points. We call this feature "custom calibration," because it allows the user to adjust the
indication at the desired points, resetting to zero the error on these points. Between the inserted points, the adjustment is
done linearly, depending on the entered values. It is important to point out that the insertion of custom calibration points
is optional, available only to those who want to adjust the indication with a local standard, because
FieldLogger
already
comes fully calibrated from the factory.
Whenever you change the input type, make sure that the custom calibration points of the previous input
are deleted!
For each channel, you must assign a unique name (tag), 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, you can assign the unit for the
measured value: when temperature sensors (Pt100, Pt1000 or thermocouples) are involved you must choose between
Centigrade (°C) and Fahrenheit degrees (°F); when linear sensors (voltage or current) are involved, you can type the
desired unit.
In the case of linear input types, you should choose what the indication range of the channel is, in other words, what the
channel must indicate when the input is at its minimum value and what it should indicate when at its maximum value
(minimum and maximum values considering the working range of the
FieldLogger
for the selected input type). Example:
selecting the 4-20 mA input type connected to a 0 to 2 bar pressure transmitter. In this case, we must choose the
minimum value in the configuration of the input "0.0" and the maximum value "2.0". All the available resolution and
accuracy will be contained in the selected range.
When using any equipment on analog inputs that are connected to the power network (for example: thermocouples or
voltage simulator), it is recommended not to use the USB interface for communicating. In some cases, it was noticed the
occurrence of noise and offsets in the readings due to the influence of the USB cable connection, probably due to ground
loops.
DIGITAL INPUTS/OUTPUTS
FieldLogger
has eight digital channels that can be individually configured as inputs or outputs.
Channels configured as inputs, if enabled, may be logged in memory, used as alarm inputs and as operands of virtual
channels. Channels configured as outputs are "open-drain" type and may be triggered by alarms or triggered via external
Modbus commands.
The digital inputs have two (floating point) values associated with their logic states during the equipment configuration.
Depending on the input’s current logic state ("0" is equivalent to a low voltage or a closed contact in the input; "1" is
equivalent to a high voltage or an open contact in the input), this corresponding value is used by the virtual channels,
alarms and logs.
The digital outputs configured to be controlled by the alarms cannot be triggered by external Modbus commands.
Likewise, the outputs configured to be controlled by external Modbus commands cannot be used by the alarms.
The outputs controlled by external commands can be used, for example, as control outputs or alarm outputs of SCADA
software or PLCs.
The digital inputs/outputs terminals are not isolated from the analog inputs terminals!
Do not use analog and digital signals coming from the same voltage source; this will cause the
equipment to malfunction.
