Siemens SM 1231 analog input signal modules convert analog signals from the process into digital signals for internal processing by the SIMATIC S7-1200.
The SM 1231 RTD modules enable temperatures to be measured with high precision using resistance-based temperature sensors. The sensors are connected directly to the module without amplifiers. All RTDs must be of the same type. The sensors can be connected with two to four cables.
The SM 1231 thermocouple modules enable temperatures to be measured with high precision using established thermocouples. In addition, low level analog signals in the ±80 mV range can be recorded. Four thermocouples each of types J, K, T, E, R, S and N can be used. They are connected directly to the module without amplifiers. For maximum possible measurement and repeat accuracy, the thermocouple modules should be mounted in locations with low temperature variations.
Other modules for the SIMATIC S7-1200 include the SM 1238 Energy Meter Module, an ideal entry into machine-level energy management. The space-saving expansion module is just 45-mm wide, and can be used to record energy flows directly on the machine. The measurements are processed directly in the CPU, and visualized with a Basic or Comfort Panel.
The SM 1238 records measured electrical values, such as voltages up to 480 VAC, in a 1- or 3-phase network with a direct connection but without a transformer. The user can freely adjust the diagnostic parameters for over and undervoltage, overload, tolerance value and tolerance time. An external 1- or 5-ampere current transformer with a conversion factor of up to 10,000 is used to measure the current.
Lastly, the SM 1234 Hybrid Module is an analog hybrid module that offers digital inputs and outputs in one module with a small footprint.