ABB i-bus KNX, Руководство по эксплуатации продукта, Страница: 236 / 264

ABB i-bus
®
KNX
Commissioning
234 2CDC508134D0202 | FCA/S 1.x.x.1
3.3.5.3 Communication objects Temperature sensor
No. Functionality communication object name Data type Flags
90 Output value Input a: Temperature sensor 2 byte
DPT 9.001
C, R, T
This communication object is used to send the output value to the bus.
The output value can be
sent as a 2-byte value [EIB floating point] EIS 5
DPT 9.001.
What is sent at an undershoot or overshoot of 10 %?
Up to an overshoot of 10 % the measured value is shown and sent. Applies for both the upper and lower limits. Furthermore,
the measured value continues to be sent as a
Measured value +10 % .
The following must be observed, particularly with the lower limit:
This only applies if the lower limit of 0 is different. If the lower limit is 0, it is not possible to determine an undershoot.
91 Request output value Input a: Temperature sensor 2 bit
DPT 1.009
C, W
This communication object appears if the output value On request is to be sent.
If a 1 is received at this communication object, the current output value is sent once from the communication object Output
value
– Input a
.
92 Measured value out of range Input a: Temperature sensor 1 bit
DPT 1.001
C, W
Telegram value: 1 = Measured value out of range
0 = Measured value in range
The communication object can be used to check the short-circuit detection of the sensor. The check is repeated with every
measurement.
When is the value of the communication object sent?
Measured value out of range is sent if the measured value exceeds the lower or upper limit by more than 5 %.
The following must be observed, particularly with the lower limit:
This only applies if the lower limit of 0 is different. If the lower limit is 0, it is not possible to determine an undershoot.
Behavior with PT100 or PT1000?
The following applies with the calculation of the maximum and minimum output values with the PT100/1000:
The lowest measurable resistance with the PT100 is about 80 ohms (with the PT1000 800 ohms) and corresponds to about -
50 °C.
The highest measurable resistance with the PT100 is about 157 ohms (with the PT1000 1,570 ohms) and corresponds to
about +150 °C.
Important
The programmable feeder line resistance is subtracted from the measured resistance. Thereafter, a programmable
temperature offset is added.
Depending on the programming of the feeder line resistances and the temperature offset, different minimum and
maximum values result.
If the sensor goes open circuit, the highest possible positive temperature value in °C is sent. If the sensor goes short
circuit, the lowest possible negative temperature value in °C is sent. The sent temperature values are dependent, for
example, on the temperature sensor used, on the line error, ambient temperatures, etc.
Behavior with a floating contact?
The communication object has no function with the selection.