Standard■Operating■Mode; Fault Mode - Johnson Controls VA-77 Series Product Bulletin

Standard■operating■mode
The LED display indicates the actuator stem position.
The LED stops flashing when the position corresponding to the
control signal has been reached.
Actuator stem moving
between 40 to 60% of stroke
Actuator■status■indication■■
(Proportional models only)
The actuator microprocessor carries out a failure diagnosis when
a failure has been detected.
The actuator status is indicated by the LED display.
LED■definition
LED permanently ON
LED flashing
LED permanently OFF
When the micro processor detects that the stem has come to an
unexpected stop it initiates a retry cycle, this is repeated three
times and if unsuccessful the actuator status is switched to fault■
mode and the LED indicate a general alarm code. If the problem
is cleared however, the actuator continues normal function.
Actuator stopped
between 40 to 60% of stroke
PB_VA-7700_Electricl Valve Actuators_02 2011
Fault■mode
If the actuator enters fault mode, the LED will flash as shown.
The indication is general and is displayed when:
• Stem comes to unexpected stop; retry cycle fails
to clear problem
• Freely defined control-signal settings are
incomplete or not stored.
• Invalid E PROM parameters
2
Specific■fault■indication
To indicate the specific fault press one of the calibration buttons
for 2■seconds. A fault diagnosis is displayed:
Specific■alarm■codes■displayed■by■LED
A B
A Calibration interrupted before completion or values missing
B Invalid E PROM parameters
2
C Actuator stalled due to valve blockage
D Default E PROM parameters defective
2
When the problem has been solved, pressing one of the■
calibration■buttons for at least 5 seconds will cause the actuator
to leave the fault mode and the LED will show present actuator
status. Standard operating mode.
C
Diagnosis
D
6