About

SIMATIC S7-300 – Analog Input Module SM 331 (6ES7331-7PF01-0AB0)

• Type: Analog input module, isolated, 2/3/4-wire
• Channels: 8 AI
• Supported Sensors: Resistor, Pt100/Pt200/Pt500/Pt1000, Ni100/Ni120/Ni200/Ni500/Ni1000, Cu10
• Resolution: 16-bit
• Module Width: 40 mm
• Height: 125 mm
• Depth: 120 mm
• Weight: 272 g
• Front Connector: 40-pin

Supply Voltage

• Load voltage L+: 24 V DC (reverse polarity protected)

• Current from L+ (without load): max. 240 mA

• Current from backplane bus 5 V DC: max. 100 mA

• Power loss: typ. 4.6 W

Analog Inputs

• Number of Inputs: 8

• Input Types: Resistance, Resistance Thermometer (Pt, Ni, Cu)

• Input Voltage: max 75 V (35 V continuous)

• Input Ranges:

  • Resistance: 0–150 Ω, 0–300 Ω, 0–600 Ω

  • RTDs: Pt100, Pt200, Pt500, Pt1000, Ni100, Ni120, Ni200, Ni500, Ni1000, Cu10

• Linearization: Parameterizable for RTDs

• Cable Length: Max. 200 m (shielded)

Conversion & Sampling

• Resolution: 16-bit (Two's complement)

• Integration time: Parameterizable

• Basic conversion time:

  • 1–4 channels: 10 ms/module

  • 5+ channels: 190 ms/module

  • 8 channels: 80 ms/module

• Interference suppression: 50/60/400 Hz

Encoder Connections

• 2-wire, 3-wire, 4-wire connection supported for resistors

Accuracy / Errors

• Operational error limit (overall temp):

  • Resistance: ±0.1%

  • RTD: ±1 K

• Basic error limit (25°C):

  • Resistance: ±0.05%

  • RTD: ±0.5 K

Diagnostics & Alarms

• Diagnostic alarm: Parameterizable per group

• Limit value alarm: Parameterizable

• Hardware interrupts: Channels 0–7

• Diagnostic info readable

• LEDs: Group error SF (red)

Potential Separation & Isolation

• Analog inputs: isolated between channels and groups

• Isolation tested: 500 V DC

• Between channels and backplane bus: Yes

• Between channels and electronics power supply: Yes 

Technical Details