Sentry Sample II Low Pressure Installation, Operation & Maintenance Manual page 15

Motor Diagnostics
The Motor Diagnostics routine is performed by Sample Sentry II controller if a motor
movement signal is sent to the motor and no motor movement is detected. The "no motor
movement" condition can be caused by:
ƒ Locked PRV
ƒ Faulty motor encoder or motor
ƒ Faulty output board inside Sample Sentry II controller
ƒ Faulty power or signal wiring between Sample Sentry II controller and motor
If no motor movement is detected the Sample Sentry II displays a "Motor Diagnostics"
Message on the display and performs a motor diagnostics routine which is described
below:
1. SV-1 and SV-2 valves close.
2. Sample Sentry II pulses the motor in the opposite direction of the previous motor
direction movement. It performs this part of sequence for 15 seconds. If the motor
movement is detected Sample Sentry II displays "PRV Calibration" on the display and
performs PRV calibration where Sample Sentry II determines the number of turns in
the PRV. After PRV calibration has been performed, Sample Sentry II returns to sample
mode or manual mode depending on the state Sample Sentry II was in before Motor
Diagnostics routine.
3. If 15 seconds have elapsed and no motor movement has been detected, the Sample
Sentry II pulses the motor in the opposite direction for 15 seconds. If motor movement
is detected Sample Sentry II performs PRV calibration routine.
4. If 30 seconds has elapsed since motor diagnostics have started, Sample Sentry II
displays a "MOTOR ALARM" on the display. Pressing MENU key on the keypad clears
motor alarm and Sample Sentry II runs PRV Calibration routine.
If Sample Sentry II detects Motor Diagnostics routine 5 times within an hour it displays
a "PRV MAINTENANCE REQUIRED" warning in the display, which suggests that PRV is
getting locked and requires a check or maintenance.
Motor Alarm
A Motor Alarm occurs when Motor Diagnostics time has exceeded 30 seconds without
receiving confirmation that the PRV is moving. Typically, a motor alarms occurs because
debris becomes lodged in the PRV, or the PRV's home position was set incorrectly. Follow
the below procedure to dislodge or clean any debris from the VREL valve.
Applying excessive torque on the PRV Shaft or PRV coupling will result in damage to the unit .
Follow the appropriate procedure when dislodging PRV .
1. Close the sample inlet isolation valve on the Sample Sentry II.
2. Remove power from the Sample Sentry II.
Sentry Sample Sentry II 15