Spectrum Controls 1734sc-OE2CIH - Manual (Page 45)

Chapter 4: OE2CIH and HART 4-9
User’s Manual Pub. 0300272-01 Rev. A.0

Fault Value uses the value set by the user (see below).
Program Action. While the system is idle or in program mode, the user may choose the
behavior of the outputs:

Low Clamp uses the Low Clamp Value (see below). If clamping has been
disabled, this setting is not allowed.

High Clamp uses the High Clamp Value (see below). If clamping has been
disabled, this setting is not allowed.

Hold Last State will lock the outputs to the last known value while ignoring
further changes to output words.

Program Value uses the value set by the user (see below).
Fault Value. This value determines the output during a fault condition. Fault Value is a
signed 16-bit integer. Values may range from 32767 to -32768. It may not exceed the
range set by the High/Low Clamp Limits if clamping is enabled (see below).
The Fault Value is clipped to the range limits as follows:

0 to 20 mA: 0.0 mA to 21.0 mA

4 to 20 mA: 3.0 mA to 21.0 mA
Fault Conditions
Fault conditions are:

Main CPU locks up but HART modem CPU continues to run:
-
If this condition exists after a successful configuration, the HART
modem CPU will set the output to the appropriate value based on the
Fault Action setting (described above). This condition will not allow
any updates to module or channel status bits and I/O data due to the
fact that the main CPU is non-functional. A communications fault will
exist in the rack for this module.
-
If this condition exists during power-up, the HART modem CPU will
not start, and there will be no output. A communications fault will exist
in the rack for this module.

Main CPU loses communication with HART modem CPU:
If the main CPU loses communications with the HART modem CPU for any
reason, it will consider this a Hard Fault condition (see HF channel status bit
information later in this manual).
Program Value
This value determines the output value while the system is not in Run mode. Program
Value is a signed 16-bit integer. Values may range from 32767 to -32768. It may not
exceed the range set by the High/Low Clamp Limits if clamping is enabled (see below).
The Program Value is clipped to the range limits as follows:

0 to 20 mA: 0.0 mA to 21.0 mA

4 to 20 mA: 3.0 mA to 21.0 mA
When both Fault and Program conditions exists simultaneously, the Fault condition takes
priority.
High/Low Engineering Values (User Scaling)
High/Low Engineering Values are signed 16-bit integers. Values may range from 32767
to -32768. These values are to determine the scaling of Output Words to actual current
for each channel:

For 0 to 20 mA range, the Low Engineering Value represents 0 mA; High
Engineering Value represents 20 mA.

For 4 to 20 mA range, the Low Engineering Value represents 4 mA; High
Engineering Value represents 20 mA.