Specifications
Analog Output Modules
31007715 6/2008 259
Output
Data Registers
The output data process image is a reserved block of 4096 16-bit registers (in the
range 40001 through 44096) that represents the data returned by the fieldbus
master. Each output module on the island bus is represented in this data block. The
STB AVO 1250 uses two contiguous registers in the output data block—the first for
the data in channel 1 and the second for the data in channel 2.
The two output data registers represent the channel data in the IEC data format.
When the module is configured to operate over a voltage range of 0 to 10 V, the data
has a resolution of 12 bits:
In this case, you can represent voltage data with integer values in the range
0... +32 760 in increments of 8. The value of bit 15 should always be 0. If a negative
value is sent, the output will be set to 0 VDC and an under-voltage error will be
returned. The value 32 000 produces a 10 V output, and the value 0 produces a 0 V
output. If the output value is set to 32 760 or greater, an over-voltage error (OVE) is
reported.
When the module is configured to operate over a voltage range of -10 to +10 V, the
data has a resolution of 11 bits plus sign bit:
In this case, you can represent voltage data with integer values in the range -
32 768... +32 752 in increments of 16. The value +32 000 produces a 10 V output,
and -32 000 produces a -10 V output. If the value exceeds +32 000, the output
channel reports an over-voltage warning (OVW). If the output value drops below -
32 000, the output channel reports an under-voltage warning (UVW). If the output
value goes up to +32 752, an over-voltage error (OVE) is reported, and if it drops to
-32 768 an under-voltage error (UVE) is reported.
2
14
2
13
2
12
2
11
2
10
2
9
2
8
2
7
2
6
2
5
2
4
2
3
Ignored
STB AVO 1250 Data Register Format for 0 to 10 V
1
2
34567
910111213
14
15
08
always 0
2
14
2
13
2
12
2
11
2
10
2
9
2
8
2
7
2
6
2
5
2
4
Ignored
STB AVO 1250 Data Register Format for -10 to +10 V
1
2
34567
910111213
14
15
0
8
sign bit
0=+
1=-
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