Purchase now: Wago 750-451 Resistance Input Module
Purchase now: Atlantech Drives provides you the Wago 750-451, an **8-Channel Analog Input Module** designed for direct **Resistance Measurement**. This high-density module allows you to connect up to eight resistive sensors (such as Potentiometers, NTCs, or PTCs) in a single 12mm wide block. It is widely used for position monitoring (linear potentiometers), temperature monitoring (thermistors), or simply measuring ohmic values in test rigs.
Technical Specifications and 2-Wire Connection
The 750-451 connects sensors using a **2-wire technique**. It measures resistance in configurable ranges (e.g., 0…1.2 kΩ, 0…5 kΩ depending on variant/config). By using a common reference potential, it maximizes channel count. The module converts the resistance value into a digital word with **12-bit resolution**. It is a passive input module, meaning it supplies the measurement current to the sensor automatically.
- Part Number: 750-451.
- Channels: 8 Resistance Inputs.
- Measurement Type: Resistance / Potentiometer.
- Connection: 2-Wire (Common Ground).
- Resolution: 12 bits.
- Measurement Current: Typ. 0.5 mA.
- Conversion Time: ~10 ms.
- Bit Width: 8 x 16 bits data.
- Housing: 12mm DIN Rail.
Expert Tips: The «Lead Resistance» Factor
Precision matters. Expert Tip: Since this is a **2-wire** measurement module, the resistance of your cable is added to the sensor reading. If you have 50 meters of cable, that adds several Ohms to the measurement, which can be significant for low-resistance RTDs like PT100 (where 0.39 Ohms = 1°C). The 750-451 is best suited for higher resistance sensors (Potentiometers > 1kΩ or NTCs) where cable resistance is negligible. For precise PT100 temp measurement, use a 3-wire module like 750-461.
Frequently Asked Questions (FAQs)
Q: Can I connect a 3-wire potentiometer?
A: Yes, connect the wiper to the input and one end to the common ground. The third leg (reference voltage) typically needs an external supply or a different module type if used as a voltage divider.
Q: How do I configure the range?
A: The measurement range is often set via the process image or GSD file parameters in the hardware configuration of your PLC software (e.g., TIA Portal, CODESYS).
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