S7-1500 SM Analog input modules

Analog input modules SM 531

Analog input modules record process signals such as pressure or temperature and forward them in digitalized format (16 bit format) to the control. They are suitable for measuring current (2-wire and 4-wire transducers), voltage, and resistance, as well as for the connection of resistance thermometers and thermocouples (measurement types depend on the module).

Modules with a width of 35 mm can be equipped with a front connector using screw terminal or push-in technology, the connector has to be ordered separately.
The narrow 25mm modules use a front connector with push-in technology which is included in the scope of delivery. The modules have the same mechanical structure as the 35 mm modules. They also offer the same operability and the same accessories. Moreover, the pin assignment in the wiring is unchanged. This means that circuit and wiring diagrams can be universally used. For all analog input modules the components for shielding like power supply element, shield bracket, and shield terminal are included in the scope of delivery

The narrow 25 mm modules can be mixed with the 35 mm modules as required.

Expanded functions for analog inputs
Oversampling (for SM 531 AI 8XU/I HS)
The use of the oversampling function requires an isochronous configuration. For analog input modules, the preset transmit clock is divided into up to 16 time-equidistant subcycles. The module reads in a measured value in each subcycle and saves it. The read in measured values of a data cycle are copied to the interface module (IM) of the ET 200MP in the next transmit clock and are available to the processing CPU one transmit clock later. A major advantage of Oversampling is that no faster CPU-Cycle is required for recording the high temporal resolution measurements.
Scaling of the measured values (for SM 531 AI 8XU/I HF)
With scaling of the measured values, the value corresponding to the technological quantity of the process can be assigned to the physical measured values of the module (current or voltage). This saves time and memory during program processing in the CPU, as the analog input module converts the physical value directly and makes it available to the user program as 32-bit floating point value (REAL).
Measuring range adjustment (for SM 531 AI 8XU/R/RTD/DC HF)
The measuring range adjustment to the used sensor enables you to increase the resolution for a configurable section of the measuring range in S7 format. Sensors frequently do not use the entire nominal range of a module but only return voltage values in a partial range. By configuring the sensor limits in the TIA Portal, the original measuring range is expanded. The resolution of the measured values is more detailed.
Calibration at RUN (for SM 531 AI 8XU/I HF and SM 531 AI 8 XU/R/RTD/TC HF)
Repeated calibration may be particularly useful for plants in which sensors measure or process relatively small voltages or currents. Recalibration compensates for any effects on the measurement result caused by cables, temperature or sensor and can be executed in RUN of the CPU. Thereby, the latest values are acquired and saved retentively on the module.
Scalable temperature measurement range (for SM 531 AI 8 XU/R/RTD/TC HF)
To keep the process temperature at a constant operating point, the module must provide a relatively high resolution. Therefore, the operating point of the process gets defined as "measuring range mean". By limiting the measuring range to a smaller area, the 16-bit resolution of the module can be applied to this range which permits a significantly higher resolution of the measurement and therefore accurate calculations.

Analog input modules with 35 mm width

SIMATIC ET 200 MP Analogeingabemodul 35mm Breite

SM 531 AI 8xU/I/RTD/TC ST

Standard analog input module with 8 channels (resistance and resistance thermometer measuring limited to 4 channels)

measurement types: current, voltage, resistance,

resistance thermometers, thermocouples
resolution 16 bits
accuracy +/-0.3%
one potential group
common mode voltage 10 V
parameterizable diagnostics
hardware interrupts (two upper and lower limits)
calibration during execution time
Article No.:

6ES7531-7KF00-0AB0

SM 531 AI 8xU/I HS

High Speed analog input module with 8 channels

measurement types: current, voltage
resolution 16 bits
accuracy +/-0.3%
one potential group
common mode voltage 10 V
parameterizable diagnostics
hardware interrupts (two upper and lower limits)
high-speed module with 8 channels in 62.5µs
isochronous mode
calibration during execution time
Article No.:

6ES7531-7NF10-0AB0

SM 531 AI 8xU/I HF

High Feature analog input module with 8 channels

measurement types: current, voltage
resolution 16 bits
accuracy +/-0.1%
eight potential groups
common mode voltage 30 VAC / 60 VDC
parameterizable diagnostics
hardware interrupts (two upper and lower limits)
Article No.:

6ES7531-7NF00-0AB0

SM 531 AI
8xU/R/RTD/TC HF

High Feature analog input module with 8+1 channels

measurement types: voltage, resistance, resistance thermometers, thermocouples
resolution 16 bits
accuracy +/-0.1%
eight potential groups
common mode voltage 30 VAC / 60 VDC
parameterizable diagnostics
hardware interrupts (two upper and lower limits)
characteristics according GOST, Integrated 9th channel for TC compensation or “real” channel
calibration during execution time
Article No.:
6ES7531-7PF00-0AB0

Analog input module with 25 mm width

SIMATIC ET 200MP Analoges Eingabemodul 25mm Breite

SM 531 AI 4xU/I/RTD/TC ST

Standard analog input module with 4 channels (resistance and resistance thermometer measuring limited to 2 channels)

measurement types: current, voltage, resistance,

resistance thermometers, thermocouples
resolution 16 bits
accuracy +/-0.3%
one potential group
common mode voltage 10 V
parameterizable diagnostics
hardware interrupts (two upper and lower limits)
calibration during execution time
Article No.:

6ES7531-7QD00-0AB0