Accuracy/Resolution
15
Siemens Industry, Inc.
125-5065T
2012-08-06
Figure 8:
6 Point Analog PPM without DOs.
Change of Value Implementation
Change of Value (COV) on the MS/TP PPM is implemented as follows:
Broadcast only on the same network as the initiated device. (Not a global
broadcast) This reduces network traffic to only the local MS/TP network in which
the PPM with COV’s resides.
COVs can be turned on or off by writing to binary output 80 (Enable COV). The
COV limit is user configurable over the MSTP network, and can be adjusted down
for better resolution or up for less network traffic.
Default COV limit is 0.5 for AI’s and AO’s; thermistor (NTC10K, Ni1000& Pt1000)
0.5F; 0-10V or 4-20 mA 1%.
MaxInfoFrames is configurable from 1 to 15; the default is 12. This variable
specifies the maximum number of information frames (COVs) the node may send
before it must pass the token.
Accuracy/Resolution
Signal
Accuracy
Resolution
Range
Ni1000
32.9°F (0.5°C)
32.2°F (0.1°C) -4 – 302°F (-20°C – 150°C)
Pt1000
32.9°F 0.5°C
32.2°F (0.1°C) -4 – 302°F (-20°C – 150°C)
NTC10k
33.0°F(0.56°C)
32.3°F(0.14°C) -13 –165.2°F(-25
℃
– 74°C)
4 to 20 mA
200uA
100uA
4 to 20 mA
0 to 10V input
100mV(1%)
50mV
0 to 10V
0 to 10V output
100mV(1%)
30mV
0 to 10V
Table 1:
