4
CHECKBACK – Device status
Each bit can be masked individually for cyclic communication by the class 2 master. This al-
lows a targeted selection to be made from the active alarms.
Byte Bit
Name
Description
0
0
CB_FAIL_SAFE
Fail-safe position:
The fail-safe position has been trig-
gered. This may have been caused by the local operation,
activation of the SET_ FAIL_SAFE_POS option or due to a
communication failure.
R
1
CB_REQ_LOC_OP
Request for local operation:
This is set when the initializa-
tion key of the local operation is activated.
A
2
CB_LOCAL_OP
Local operation:
•
The device has been switched to the MAN or SAFE
mode by the local operation.
•
The device is in the self-testing mode (initialization, zero
point calibration or diagnostic function active). In this
case, the CB_SELFTEST bit is also set.
R
0
3
CB_OVERRIDE
Operating voltage for the optional integrated solenoid
valve failed:
The positioner cannot function and moves to
the fail-safe position determined by the actuator, regard-
less of the reference variable.
R
4…6 Not assigned
7
CB_TRAVE_TIME
Control loop error:
The control valve no longer follows the
controlled variable in the tolerable times (see error code 57
in EB 8384-4 EN).
This alarm is reset after 10 seconds. The message
CHECKBACK byte 1 bit 5 remains, in contrast, until it is
confirmed.
A
1
0…1 Not assigned
2
CB_UPDATE_EVENT
Static data changed:
This is set when the device data have
been changed, allowing (unintended/unauthorized)
changes from the originally set values to be monitored.
A
3
CB_SIMULATE
Simulation mode active:
This is set when the simulation
mode of at least one Function Block is active.
The simulation mode of the AO Function Block allows the
controlled variable x to be simulated.
The simulation mode of the DI Function Block allows the
discrete output to be simulated.
R
4
Not assigned
KH 8384-4 EN
15
CHECKBACK – Device status
Summary of Contents for 3730-4
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