Class1 3041-10X-00-CL1 - Sentry Governor - EXTERNAL - Manual (Page 19)

FORM-ENG-0018 REV A 05-27-03
607 NW 27th Ave
Ocala, FL 34475
Ph: 352-629-5020 or 1-800-533-3569
Fax : 352-629-2902 or 1-800-520-3473
TECHNICAL DATA SHEET
PAGE
18 OF 36
DATE 6/19/2014
PRODUCT GROUP THROTTLE CONTROL P/N 3045-101-00-CL1, 3045-102-00-CL1 REV 1.02
PRODUCT SENTRY PRESSURE GOVERNOR BY AMS
5.3.1. Intake or Discharge Sensor Fault
The Intake and Dischgarge Sensor Fault warning messages indicate that the associated pressure sensor signal
voltage is out of range (<0.30 VDC or >4.90 VDC). When this occurs the SENTRY does not have valid pressure
data and responds by switching operation to THROTTLE mode (where pressure data is not required). There are
typically four reasons the pressure sensor voltage is out of range:
•
The pressure sensor is damaged.
•
The pressure sensor signal wire is broken.
•
The pressure sensor ground wire is broken (signal voltage will be at 5.00 VDC).
•
The pressure sensor supply voltage wire is broken (signal voltage will be at 0.00 VDC).
5.3.2. Water Supply Insufficient, Discharge Pressure Less Than 30 Psi, and Critical: Sentry In Stand By. Check
Water Source
Water Supply Insufficient, Discharge Pressure Less Than 30 Psi, and Critical: Sentry In Stand By. Check
Water Source work together and in sequence when the discharge water pressure cannot be maintained due to
cavitation or inadequate water supply.
•
The Water Supply Insufficient message appears first after the SENTRY has attempted to maintain
discharge pressure by increasing the engine RPM. Failing to maintain the discharge pressure, the
SENTRY drops the engine speed to 1100 RPM and begins increasing the RPM as part of the Supply
Intake Protection (SIP) routine.
•
The Discharge Pressure Less Than 30 Psi message appears after the Supply Intake Protection (SIP)
routine has failed and the discharge pressure has dropped below 30 PSI. The SENTRY maintains the
engine speed at 1100 RPM for the time period defined by the pressure time-out variable (3 seconds
default, see section 6.6.8).
•
The Critical: Sentry In Stand By. Check Water Source message appears after the SENTRY has
switched to STANDBY mode (IDLE). This message informs the operator that the SENTRY could not
maintain a discharge pressure of 30 PSI or more. The water supply must be verified.
5.3.3. Unable To Maintain Discharge Pressure
The SENTRY in PRESSURE mode maintains the operator set discharge pressure by adjusting the engine RPM.
The SENTRY increases the engine RPM to return to the operator’s set discharge pressure when a pressure drop is
detected. The SENTRY maintains the Limit RPM and displays the warning message when the SENTRY cannot
fully regain the operator’s set discharge pressure.
Limit RPM = RPM
STASIS
+ RPM
RANGE
RPM
STASIS
= Engine RPM where operator’s pressure was last stable.
RPM
RANGE
= Engine RPM increase range (300 RPM if RPM
STASIS
< 1500, 200 RPM if RPM
STASIS
> 1500)
For example: The SENTRY is maintaining the operator’s set discharge pressure of 100 PSI at 1100 RPM. The
pressure drops to 90 PSI and the SENTRY compensates by increasing the engine RPM. The SENTRY continues
increasing engine speed until 1400 RPM is reached but the discharge pressure has only increased to 92 PSI so the
SENTRY maintains 1400 RPM and displays the warning message.
5.3.4. Discharge Pressure Has Increased More Than 50 Psi Since Setting Rpms
The SENTRY in THROTTLE mode maintains the operator set engine RPM. But the SENTRY will limit the
discharge pressure if the pressure recorded when the RPM was last set has increased more than 50 PSI. The
SENTRY will reduce the engine RPM to maintain the pressure increase to no more than a 50 PSI differential and
display the warning message. The SENTRY does not attempt to regulate pressure while in THROTTLE mode, but
it will attempt to limit a pressure increase to a maximum of 50 PSI over the pressure detected when the operator set
the desired engine RPM.