1/7/2019 6:56 PM | |
Joined: 9/27/2006 Last visit: 2/19/2025 Posts: 12337 Rating:
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Hello RScott; Notice the possible voltage and current configurations for analog SMs of the S7-1200: SM 1234 AI 4 x 13 bit / AQ 2 x 14 bit: Range ±10 V, ±5 V, ±2.5 V, 0 to 20 mA, or 4 mA to 20 mA SM 1234 AI 4 x 13 bit / AQ 2 x 14 bit Range: ±10 V or 0 to 20 mA Voltage signals are bipolar (they go from -10 V to +10 V, for example, values can be negative) current signals are unipolar (all positive values, 0-20 ma, 4 to 20 mA). So for voltage signals, the rated analog value representation will also be bipolar, and vary between -27648 and +27648, whereas for current (unipolar) signals, the rated analog value representation will vary from 0 to +27648. This can be seen from the analog value representation tables, copied below (from the S7-1200 System manual: https://support.industry.siemens.com/cs/ww/en/view/91696622). The reason Siemens has chosen these ranges is to standardize all analog measurement and facilitate conversions (scaling) to engineering values, since the analog values are now independent of individual analog module resolution. Hope this helps, Daniel Chartier |
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1/8/2019 4:06 PM | |
Posts: 121 Rating:
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Thanks for the help team sometimes just finding the docs is 90% of the battle |
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