Bronkhorst EL-FLOW Prestige - Manual (Page 47)

Bronkhorst High-Tech B.V.
EL-FLOW Prestige 47 9.17.084
5.2 Troubleshooting
In this section a number of possible errors/malfunctions of the instrument are listed.
LED indications
See section 3.7 for interpretation of specific LED indications of the instrument
Factory reset
In case (re)setting of the instrument has led to unexpected or non-recoverable behavior, it is possible to reset the instrument to the
settings applied at the factory during production. Use the 'Restore Settings' tab under 'Instrument Settings' in FlowPlot or use the
micro switch on top of the instrument (section 3.8) to restore the instrument to the original factory settings. Note that any
changes made to the instrument communication settings will not be restored after a factory reset. If digital communication with
the instrument can not be re-established, see section 3.4 to overrule the actual 9-pin sub-D communication settings with the
'Configuration Mode' (using the micro switch) and use the RS232 communication mode to re-establish communication.
Troubleshooting list
Symptom Possible cause Action
No power (LEDs not burning) No power supply Check power supply
Check cable connection
Internal fuse blown due to long lasting
shortage
Return to factory
Zero output signal No setpoint accepted, incorrect control
mode
Check analog/digital control mode
(section 4.2.2)
No setpoint given, setpoint too low Give setpoint >2%
Valve in 'Safe State' (normally closed
valves)
Remove cause of 'Valve Safe
State' (see section 3.1.2)
Pcb/sensor failure Return to factory
Laminar flow element blocked/
contaminated
Return to factory
Maximum output signal (131.07%) Flow too high, valve fully open Close valve
Pcb/sensor failure Return to factory
Valve in 'Safe State' (normally opened
valves)
Remove cause of 'Valve Safe
State' (see section 3.1.2)
Setpoint cannot be achieved Pressure difference across instrument
insufficient to achieve requested flow rate
Check inlet/outlet pressure
Valve blocked or damaged Return to factory
Stoppage Remove contamination
Flow signal is gradually decreasing without
setpoint change
Pressure difference across instrument
insufficient to achieve requested flow rate
Check inlet/outlet pressure
Process gas condensation occurs Decrease pressure or increase gas
temperature
Oscillating controller output Controller adjustment wrong, PID settings
too fast
Set ' 254 Controller Speed (Kspeed)' to
lower value
Inlet/outlet pressure too high or too low Adjust pressure/set correct
instrument pressure with FlowTune
Wrong gas selected Set correct process gas with FlowTune
Inlet pressure control is oscillating Replace pressure regulator or increase
buffer volume between controller
instruments (section 2.3)
'Cross-talk' with other controller
instruments in process line
Increase buffer volume between
controller instruments (section 2.3)
Valve is damaged Return to factory
Non-zero output signal when valve is closed Valve is leaking (through valve) Check valve specifications for leak-