VBA-2E-G11-I/U/PT100-*
Appendix B
2014-
02
21
Pt100 Input Measurement Ranges
Pt100: -200
°
C ... 850
°
C
9.2
Delay Times
The VBA-2E-G11-I/U/PT100-* needs a certain amount of time for the conversion and
transmission of the analog measuring signals on the AS-Interface master. This period of time is
mainly composed of the conversion time and the transmission time. The conversion time and
transmission time depend on a number of factors.
Latency
Latency = delay of a signal under worst case conditions.
The analog-to-digital conversion in the analog module and the transmission via AS-Interface is
not in sync. In the worst case, the transmission of a channel via AS-Interface starts just before
the conversion of this channel is completed within the module. This gives rise to two scenarios:
1. The conversion time is longer than the transmission time
Latency = Conversion time + Transmission time * (Number of ch1)
2. The conversion time is shorter than the transmission time
Latency = Conversion time * (Number of ch1) + Transmission time
Figure 9.1
Conversion time > Transmission time
Caution!
Maximum input voltage
The input voltage at the voltage input must not exceed 50 V.
Input signal [V]
Display on the master Input LED
> 884
°
C
32767
Flashing
Above threshold
(peripheral fault)
850.1
°
C ... 884
°
C
8501 ... 8840
On
Extended range
1)
-200
°C ... +850 °C
(18.52
-2000 ... 8500
On
Nominal range
-219.4
°
C ... -200.1
°
C -2194 ... -2001
On
Extended range
1)
< -219.4
°
C
32767
Flashing
Below threshold
(peripheral fault)
Table 9.4
Measurement range -219.4
°
C ... 884
°
C
1)
: Measurement accuracy corresponds to the nominal range
1st
Module
Analog-to-digital conversion
Channel 1
Analog-to-digital conversion
Channel 2
Analog-to-digital conversion
Channel 1
Transmission
Channel 1
Transmission
Channel 2
Transmission
Channel 2
Transmission
Channel 1
Conversion time
~ Transmission time x 3
Network
