X20 system modules • Analog output modules • X20AO2438
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X20 system User's Manual 3.10
4.4.3.10.4.2 DACSlewrate
Name:
DACSlewrate01 to DACSlewrate02
These registers limit the rate at which the analog signal is modified. This makes it possible to define a sort of upper
limit frequency.
The following formula
applies:
f(Analog) = f(Output rate) * Permitted change / max. ∆(standardized output value)
Data type
Value
UINT
See bit structure
To ensure communication takes place without errors, it's important that the frequency range of the digital HART
signal is not influenced by the analog output. HART communication takes place in the frequency range 950 to
2500 Hz.
Example (default):
Conclusion:
f(Analog) = 152440 Hz * 4 / (32767 - 0)
f(Analog) = ~
20 Hz << 950 Hz
= f(HART)
Bit structure:
Bit
Name
Value
Information
000
1-bit
001
2-bit
010
4 bit (bus controller default)
011
8-bit
100
16-bit
101
32-bit
110
64-bit
0 - 2
Permitted change per rate
111
128-bit
3 - 7
Reserved
-
0000
257730 Hz
0001
198410 Hz
0010
152440 Hz (bus controller default)
0011
131580 Hz
0100
115740 Hz
0101
69440 Hz
0110
37590 Hz
0111
25770 Hz
1000
20160 Hz
1001
16030 Hz
1010
10290 Hz
1011
8280 Hz
1100
6900 Hz
1101
5530 Hz
1110
4240 Hz
8 - 11
Output rate
1111
3300 Hz
12 - 14
Reserved
-
0
Disabled (undefined jump behavior)
15
Slewrate enable
(ramp functionality)
1
Enabled (defined transitions)
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