The following three causes are most likely.
Cause 1. The sensor is wired incorrectly.
- When using a 3-wire sensor, connect to terminal 10 (power supply +), terminal 11 (power supply −), and terminal 1 (output).
- When using a 2-wire sensor (NPN open-collector output), connect to terminal 11 (power supply −) and terminal 1 (output).
- When using a relay contact or Solid-state Relay (NPN open-collector output), connect to terminal 11 (power supply −) and terminal 1 (output).
- When using a sensor's voltage pulse output or a Mitsubishi inverter's FM output terminal, connect to terminal 3 (+ side) and terminal 11 (power supply −).
Note: The FM output from a Mitsubishi inverter is a voltage pulse output.
| NB: NPN input or voltage pulse input connections | PB: PNP input connection | ||
| NPN open-collector output or NPN DC 2-wire output |
Contact output | Voltage output | PNP open-collector output |
 When using an NPN DC 2-wire sensor, input +V to terminal 1 and -V to terminal 11. |
 When shorted, about 12 V and 13 mA (nominal) will flow. |
 |
 With using a voltage pulse input that is not from a 3-wire sensor, input +V to terminal 3 and -V to terminal 11. |
Cause 2: The sensor's capacity does not match the K3NR.
Check the sensor's leakage current. When connecting to a K3NR, select a sensor with an OFF leakage current of 1.5 mA max.
It is especially important to have an appropriate leakage current when using a 2-wire sensor or Solid-state Relay.
Cause 3: The auto-zero time setting is too short.
The K3NR calculates the predicted pulse interval in order to predict when the next pulse will be input. If a pulse input is not received within a certain time, it is necessary to indicate that rotation has stopped (set display value to 0), and the auto-zero time specifies how long the K3NR will wait before determining that rotation has stopped. If this auto-zero time is set to a value shorter than the pulse interval, the display is forcibly set to zero.
First, restore the auto-zero time to its default setting (X = 9.9999, and Y = 10 E 9).
If it is verified that measurements can be taken, set the auto-zero time to a value appropriate for your application.