5. DESCRIPTION OF FUNCTION VM-5S
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5-1 DISPLAY
Rotor speed, speed comparison setting value, and sensor set gap voltage are normally displayed on
individual LCD for each channel.
5-2 SPEED RELAY FUNCTIONS
The VM-5S Dual Tachometer is provided with a speed relay function to monitor the rotation speed.
The following two speed relay types are available.
• OVER SPEED Type When the rotation speed exceeds the set value, speed
relay is contact-output and the speed relay lamp lights.
• UNDER SPEED Type When the rotation speed drops below the set value, speed
relay is contact-output and the speed relay lamp lights.
5-3 OK (INPUT ABNORMAL ALARM)
When the level of the signal from the transducer becomes abnormal, OK alarm outputs and LCD is
flashing. This condition is maintained by the off-delay timer for approx. 15 sec. after the level of
the transducer signal has returned to normal.
Input type Detectable input abnormal conditions
VK Transducer
Sensor is short-circuited.
Extension cable is short-circuited.
Sensor set gap is too small.
Cable is short-circuited or broken between transducer and monitor.
RD Tacho Driver
FK Driver
Sensor is short-circuited or broken.
Extension cable is short-circuited or broken.
Sensor set gap is too small.
Cable is short-circuited or broken between transducer and monitor.
MS Magnetic Pickup
Magnetic Pickup is broken.
Cable is short-circuited or broken between Magnetic Pickup and
monitor.