How do I read and zero the Rokae dual-channel torque sensor?

Read the two channels from:

• PDO 0x2401 → ch1
• PDO 0x2402 → ch2

Both values are in mV. The average sensor voltage is V_avg = (ch1 + ch2) / 2.

For zero calibration, with the joint completely unloaded, set V_zero = (ch1 + ch2) / 2. Average multiple readings over time while doing this to reduce noise.

Torque is then T = ((((ch1 + ch2) / 2) - V_zero) / 1000 / Linear_Coefficient) × Range, with T in N·m. The standard linear coefficient is 2.25 for typical single-sensor calculations. For a complete robot assembly the coefficient may need to be determined manually or provided by Rokae.

Adding the troubleshooting checklist we use, since it comes up right after people get the formula working:

• No sensor voltage at all: check sensor power, and confirm you are reading the correct PDO addresses.
• Reading sits near zero or full scale after operation: possible sensor failure, electrical interference, or an internal wiring/connection problem.
• Calculated torque doesn't match the applied load: recheck V_zero, verify the linear coefficient, and verify the sign of the coefficient.