User Manual

Chapter 3 - Development Environment Landis+Gyr
32 98-1138 Rev AD Gridstream SCADA/DA S4SBR
Analog Input Functionality
This device provides two general purpose analog inputs. These are filtered and connected to a 10-bit
A/D converter.
 NOTE: The voltage reference for this A/D converter is 2.5 VDC +/- 60[mVDC] across the operating
temperature range.
This A/D converter has the following specifications:
 NOTE: The actual sampling time is 0.25 μS and the conversion time is 2.75 μS, but the rate at which
signals on these inputs can be sampled in-practice is limited by the DCW execution. It is
recommended that these channels be used only for DC voltage measurement, and that the
sampling rate can not exceed 100 mS.
The register below can be used to control either of the two general purpose Analog pins (A1 & A2)
located at memory location 7701 (hex).
Table 3 - 2. A/D Converter Specifications
A/D characteristic Specification
Resolution 10 bit
INL +/-5 LSB
Absolute Accuracy +/-5 LSB
DNL +/-1 LSB
Offset Error +/-3 LSB
Gain Error +/-3 LSB
Table 3 - 3. Control Register 2
Bit Feature Description Dflt.
0Pin A1 Direction
0: Input
1: Output
0
1 Pin A1 State
When A1, bit 0 is "0" and bit 2 is "0", then bit 1 returns current state as
"0" or "1".
When A1, bit 0 is "0" and bit 2 is "1", then read location 7702-7703
which returns the Hex value of the sampled voltage between 0-2.5
VDC.
When A1, bit 0 is "1", then the value of bit 1 can be set.
0
2Pin A1 Control
0: General Purpose I/O
1: Analog to Digital Channel (Bit 0 = "0" only)
0
3 Reserved Not Used 0
4Pin A2 Direction
0: Input
1: Output
0
draft 29 Jan 2013