Programming with TAPPS2 / DL bus
35
Sensor check
If you set the sensor check to "
Yes
", the
sensor error
of the sensor supplying the DL input is available
as an input variable for a function.
Sensor error
This setting is only displayed if
sensor check is active
and the measured variable is set to
"
User def.
".
If the "
Sensor check
" is active, the
sensor error
from a DL input is available as a function input
variable: status "
No
" for a sensor that is working correctly and "
Yes
" for one that is faulty (short circuit
or lead break). This allows the controller to react to the failure of a sensor, for example.
If the
Standard
thresholds are selected, a short circuit will be indicated if the value falls below the
measurement limit
and a lead break will be indicated if the value exceeds the
measurement limit
.
The
Standard
values for temperature sensors are -9999.9 °C for a short circuit and 9999.9 °C for a
lead break. Those values are utilised in the internal calculations in the event of an error.
By selecting suitable thresholds and values for a short circuit or lead break, a fixed value can be
specified for the module in the event of sensor failure, to allow a function to continue operating in
emergency mode (fixed hysteresis: 1.0 °C).
The short circuit threshold must be defined below the lead break threshold.
In System values / General, a sensor error for
all
inputs, CAN inputs and DL inputs is available.
DL digital inputs
The DL bus is configured for the transfer of digital as well as analogue values. However, there is not
yet any use for this at present.
The parameters are programmed in almost exactly the same way as for the DL analogue inputs.
Under
Measured variable / User def.
the
display
for the DL digital input can be changed to
No / Yes
.
Bus load from DL sensors
A 2-pole cable provides
both
the power supply and the signal transfer for DL sensors. An additional
power supply by means of an external power supply unit (such as with the CAN bus) is not possible.
