Used Yokogawa 701281 2 Channel Frequency Module

Product Highlights

Measurement frequency of 0.01 Hz to 500 kHz, Measured parameters (frequency, rpm, period, duty, power supply frequncy, distance, speed). Applicable to DL850 series, SL1000

All the functions and performance specs required for pulse measurement packed into a small, 2 CH module.

The module's internal high-speed CPU performs measurement, calculation, and recording in real time.

• 9 measurement modes
• 0.01 Hz-500 kHz
• 1 µs (1 MHz) update rate
• Max 16 ch
• Directly records and measured results
• Unlike with FV converters, rescaling is not necessary with this module. Directly record measured results. Display numerical values directly using cursors and auto measurements.

Real-Time Digital Filtering

The DL850E/EV has 2 real-time digital filters that can be used for waveform averaging.

• Smoothing Filter (Moving Average)
• Smooth stair-step shaped waveforms. Updating occurs every 1 µs, giving a highspeed averaging effect. Filters are set at 0.1 ms-1 sec (up to the 25000th order). Filters reduce jitter in observed waveforms, and increases resolution.
• Pulse Average: Useful for determining the average value per rotation, or determining the number of rotations when a gear is missing teeth. Output is averaged every specified number of pulses (between 1 and 4096 pulses).

Variety of Signal Inputs

• Direct-Coupled Signal Input
  • Encoder pulse input of up to ±42 V.
  • Direct input to EM (electromagnetic) pickups (1:1).
  • AC power up to 300 V (10:1 isolation probe 700929 required
• Multiple Analog Inputs
  • Isolated input, 6 ranges, 4 input filters, internal pullup (mechanical contacts, supports open collector), AC/DC coupling, variable threshold value, 3 types of hysteresis
• Chatter Elimination (Supports Mechanical Contacts)
  • Time setting: 1 ms-1000 ms
• Convenient Input Presets
  • Presets for logic input (3 V-12 V), EM pickups, and AC power available in menus.

Supports Braking Applications

By predicting the deceleration curve and stop point, the module automatically compensates for the lack of information on encoder pulses which occur during deceleration.

• Deceleration Prediction (1)
• Automatically calculates and outputs a deceleration curve based on the interval of the last input pulse.
• Stop Prediction (2)
• If no pulses are inputted for a period of time, a stop is inferred, and output is set to 0. Up to 10 steps can be specified.

Offset Observation Function

An observational center (offset) is set and the area surrounding the offset can be zoomed. Useful when you wish to observe the fluctuation centering on a certain frequency.

Trigger Support

Triggers can be activated on output results from all observation modes. For example, you can observe and trigger on a duty value.

Frequency Module Applications

The 701281 Frequency Module supports all rotation and pulse measurements involved in encoder pulse measurement.

• Automotive
• For measurement of rotating devices such as engines and transmissions (rpm, speed, distance, fluctuations).
• Effective for deceleration characteristics in braking applications such as ABS. Also used for duty analysis of oil pressure controllers.
• Motor
• For measurement of rotation, load characteristics, and fluctuations.
• Robot
• For multichannel measurement of encoder pulse, and motor analysis.
• Office Automation
• Office equipment, paper feed fluctuation analysis, copiers, and wow-flutter in laser printer drums.
• Power Supply
• High resolution measurement of power supply frequency (50/60 Hz) (0.01 Hz resolution, ±0.03 Hz accuracy)

Convenient LED

An LED accompanies each channel for confirmation of pulse input. Lights green during input, and turns red on a voltage overrange. You can confirm the input waveform condition at a glance.