To complement our new High Resolution Wheel Pulse Transducer (WPT) encoder product, Michigan Scientific Corporation is offering an add-on to convert encoder pulses to proportional voltages. The EC-LV (Encoder Conditioner – Linear Voltage) reads the Phase A, Phase B , and Index pulse signals from the WPT and converts them to two analog voltage signals: one proportional to angular velocity, and one proportional to angular position. This is helpful for applications that are not using a data acquisition capable of reading high-speed encoder pulse trains. Separating the frequency-to-voltage electronics from the encoder also allows the WPT to maintain a much smaller profile, increasing the durability and longevity.
The EC-LV is powered in-line with the WPT, so there is no need for a separate power source or cable. All encoder signals are also passed through the EC-LV, so the customer has access to all data generated by the system.
The Full-Scale Velocity (equal to ±10 Vdc) is set at the factory, with two options. Standard values are 1,000 and 1,800 RPM, and the customer can select which scale to use with a toggle switch. Customers can request custom values for the full-scale velocity. Additionally, they can request a custom full-scale voltage, for systems that cannot handle 10 Vdc inputs. There is also a toggle switch to select which rotational direction (clockwise or counter-clockwise) should equate to a positive output.
How it Works
The velocity output of the tachometer board updates on the rising edge of Phase B for positive velocity, and on the falling edge of Phase B for negative velocity. The position output updates on the rising AND falling edge of Phase B. For example, with a 512 PPR (pulse per revolution) WPT, the velocity will update 512 times/revolution, and the position will update 1024 times/revolution.
Presented below are some figures showing the analog voltage outputs of the EC-LV in relation to the encoder outputs of the WPT (passed through the EC-LV). The EC-LV was set for positive outputs in the clockwise direction for all these figures. The channels are as follows:
- Channel 1: Phase A
- Channel 2: Phase B
- Channel 3: Index
- Channel 4: either Velocity or Position