Badger Meter SRD/SRI Valve Positioners - Manual (Page 39)

Fail Safe Mode
For Digital input, the operator may configure the Powerup mode to Fail safe . When using Fail safe, the you can define the exact
position of the control valve upon Powerup . Available options, listed under Fail Safe Config are as follows:
• Hold (hold last position)
• De-energize (spring uncompressed in single acting actuators)
• Fall-back position (allows the valve to go to a specified Position, in Time-out seconds after power-up) .
This parameter is not available for analog operation . The configuration Hold is the default setting .
One of the important features of the FoxCom system is to detect when problems occur and to properly handle them . For
example: if the system loses power, the actuators all de-energize and send their associated valves either to full open or full
closed depending on the definition of "energized ."
However, a more interesting case is when the FBM ceases to communicate with the positioner . Each valid setpoint command
resets a fail-safe timer on arrival . If the FBM stops sending setpoints, this timer increments until it hits a user-specified value . At
that point, the positioner automatically moves the valve to a fail-safe position (typically the de-energized position) and goes
into a fail-safe mode . The next arrival of a setpoint resets the timer, and kicks the system back into the mode it held prior to
the fail-safe .
During fail-safe mode, the status bits are changed to reflect the condition .
Fail Safe Timer
This is a 4-byte real . The parameter represents how long, in seconds, the SRD991 positioner will tolerate no setpoint
commands in communication before it enters a Fail-safe state . Zero is a special case and forces the positioner to wait forever -
that is, it will never time out and enter fail-safe . Ten seconds is the default time out period .
Spring Type
Your may specify the single-byte parameter for Spring type . The Spring Type is automatically determined during the Autostart
procedure . For single-acting with Closes or Opens; for double-acting with None .
Amplifier Type
The Amplifier Type identifies what amplifier is installed . This field is automatically identified by the Modelcode with single,
double or spool .
Actuator Action
This is a single-byte parameter . It defines the type of pneumatic actuator that is either spring loaded or an actuator with
pressure applied to both sides . The Actuator action is automatically defined by the Modelcode . It can be Single (for spring
return actuators) or Double (for double acting actuators) .
Fail Safe Timer
This is a 4-byte real . The parameter represents how long, in seconds, the SRD991 positioner will tolerate no setpoint
commands in communication before it enters a Fail-safe state . Zero is a special case and forces the positioner to wait
forever—that is, it will never time out and enter fail-safe . Ten seconds is the default time out period .
Fail Safe Fallback Position
This parameter is a 4-byte real . It represents the position that the Valve will move to when it is in Fail- safe Spring Type and the
Fallback Option have been set to use the Fallback Position . The units are position in % . Default value is 0% .
Setpoint Source
This is a single-byte field . The user may specify one of three options .
The Setpoint source can be configured to be Digital (FoxCom-Digital) or Analog (Intelligent w/o communication or HART) .
This field is automatically identified by the Modelcode .
Configuration / Parameter
Page 39 August 2014 POS-UM-00011-EN-02