Samson 4785, Mounting And Operating Instructions

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The action determined by the parameter FSAFE_TYPE (fail-safe action) is triggered by
the following events:
 Start-up (warm start) of the positioner.
 Elapsing of the DP watchdog through interruption of the cyclic communication
with a Master Class 1 (not applicable when communication is terminated
properly).
 In Automatic or Remote Cascade operating mode, when the status of the
reference variable SP or RCAS_IN valid in this operating mode is set to
"Initiate Fail Safe".
 Receipt of a DP- "Global Control" service, for which the clear bit is set.
By setting the status of the reference variable used in the valid operating mode to
"bad", the actuator always moves to the fail-safe position determined by the spring
action (for version K 1.30 and higher).
Positioner manufacturer
DEVICE_MAN_ID
Clearly identifies the manufacturer of the field device.
Read-only.
Product number positioner
DEVICE_PRODUCT_NUM (M )
Manufacturer’s product number of the positioner.
Proportional-action coefficient
KP_Y1
SERVO_GAIN_1
Proportional-action coefficient
KP_Y2
SERVO_GAIN_2
Default:
Proportional-action coefficient for supply air.
When writing, the value is written to KP_1 (supply air) and KP_Y2 (exhaust air).
Proportional-action coefficient for exhaust air.
When writing, the value is written to KP_Y2 (exhaust air). KP_Y1 (supply air) remains
unchanged.
We recommend to adjust the value in increments of 0.1 when adjusting the value in the
range from 0.01 to 10.0. If the value is increased, the set point will be reached faster.
Range: 0.01 to 10.0
1.2
Note!
When the positioner is initialized for the first time, the proportional-action coefficients
KP_Y1 and KP_Y2 are determined.
The initialization values listed in the table on the following page might have to be
adapted to the modified operating conditions in order to achieve optimum control
behavior.
Rated travel/nominal angle
RATED_TRAVEL
Default:
Rated travel [mm] or nominal angle [degree] of the valve.
Nominal operating range 0.0 to 255.9 mm or 0.0 to 120.0 degrees.
15 mm
Reference variable w
SP
Set point with status.
Reference variable in "AUTO" operating mode,
Also see reference variable range.
Reference variable w_rcas
RCAS_IN/RCAS_OUT
Set point with status.
Reference variable w in "RCAS" operating mode,
Also see reference variable range.
EB 8382-2 EN
61
List of parameters