Flowserve 3400IQ Digital Positioner - Manual (Page 81)


Logix 3400IQ Digital Positioner FCD LGENIM3402-00 – 0/07
flowserve.com
1.23 V Reference Alarm The 1.23 V reference is used by the inner-loop spool position control. If it
drifts outside normal tolerances, the 1.23 V reference alarm will become active. If a continuous 1.23
V reference alarm exists, the main PCB assembly must be replaced. Refer to the Logix Series 3400IQ
Digital Positioner IOM for spare parts kit numbers.
12-bit D/A Alarm The Logix 3400IQ digital positioner utilizes a 12-bit Digital-to-Analog (D/A)
converter to send a control signal from the micro controller to the inner-loop spool positioning
circuit. The output of the D/A converter is independently measured to verify correct operation. A 12
bit D/A alarm indicates that the D/A may be malfunctioning. If a continuous 12 bit D/A alarm exists,
the main PCB assembly must be replaced. Refer to the Logix Series 3400IQ Digital Positioner IOM for
spare parts kit numbers.
Temperature Alarm The main PCB assembly contains an ambient temperature sensor. If the
ambient temperature readings goes outside the operating range, -40°F to +185°F (-40°C to +85°C),
the temperature alarm will become active. The red LED will also blink. If this alarm is present and
the ambient temperature reading is incorrect, the main PCB assembly must be replaced. Refer to the
Logix Series 3400IQ Digital Positioner IOM for spare parts kit numbers.
Hall sensor Alarm As described in Theory of Operation in section 1, the Logix 3400IQ digital
positioner incorporates an inner-loop, spool positioning stage. A hall sensor is used for spool control.
If the electronics senses a problem with the sensor, the hall sensor alarm will become active. Some
common reasons for a hall sensor alarm are loose or missing cable connection to the collector board
assembly or a broken wire. In the rare event that the actual hall sensor is defective, the driver module
assembly must be replaced. Refer to the Logix Series 3400IQ Digital Positioner IOM for spare parts
kit numbers.
Note: A loss of air supply can trigger a Hall Sensor alarm.
Modulator current Alarm In the Logix 3400IQ the modulator current is no longer measured. The
value that is being measured is peizo voltage. If the piezo voltage is out of range, an alarm will
trigger. To determine the actual piezo voltage, read the value from MOD_Current. Move the decimal
place one to the right to obtain the actual piezo voltage. Replacement of the driver module may be
necessary if the alarm persists and the positioner does not function.
EEPROM checksum Alarm Configuration data is stored in EEPROM. When power is lost,
configuration information is retrieved from EEPROM and operation resumes. A check is done by the
micro-controller after a power-up to make sure data saved in EEPROM has not been corrupted. The
checksum is a number that is calculated based on configuration data. It is also saved in EEPROM
every time data is stored. If after a power-up, this number does not match the data in memory, an
EEPROM checksum alarm is generated and the red LED will blink. If this occurs, try powering the
Logix 3400IQ digital positioner off and then back on. If the error does not clear, try saving configura-
tion data again using FB Configurator. If previous configuration has not been saved, must be reset
and reconfigure. If these steps still do not clear the error, the main PCB assembly must be replaced.
Refer to the Logix Series 3400IQ Digital Positioner IOM for spare parts kit numbers.
Pressure Alarms
Pressure alarms are only available on models with advanced diagnostics (Logix 3400IQ digital
positioner). Advanced diagnostic models add top and bottom pressure sensors. These sensor
readings and alarms are only accessible from the communicator when the configuration has been set
to Advanced.
Loss of Pressure The loss of pressure alarm becomes active when the supply pressure is near the
minimum positioner operating pressure of 30 psig. The LEDs will blink Red, Green Yellow, Red. This
alarm is meant to alert the user to low supply pressure as well as complete loss of pressure.