OPERATION ST80/ST80L Flow Meter
62 Fluid Components International LLC
Table 15 – Command Status Bytes, Bit Assignments
Byte Bit
Response Code (No Comm Error)
Byte 0
Reserved – Bit cleared to zero.
Command-Specific Response Code (0-127)
See Table 16 below.
Buffer Overflow – The message was too long for the
received buffer of the device.
Reserved – Bit cleared to zero.
Longitudinal Parity Error – The longitudinal parity
calculated by the device did not match the check byte at
Framing Error – The stop bit of one or more bytes received
by the device was not detected by the UART (i.e., a mark or 1
was not detected when a stop bit should have occurred).
Overrun Error – At least one byte of data in the receive
buffer of the UART was overwritten before it was read (i.e.
the slave did not process incoming byte fast enough).
Vertical Parity Error – The parity of one or more of the bytes
received by the device was not odd
1: Set bit means byte represents communications error.
0: Cleared bit means byte represents response code.
Byte 1
Device
Status
Primary Variable Out of Limits – The PV is beyond its operating limit.
Non-Primary Variable Out of Limits – A device variable not mapped to the PV is beyond its operating limits.
Loop Current Saturated – The loop current has reached its upper (or lower) endpoint limit and cannot increase (or
decease) any further.
Loop Current Fixed – The loop current is being held at a fixed value and is not responding to process variations.
More Status Available – More status information is available. Refer to Command 48, Additional Device Status
Bytes, page 63.
Cold Start – A power failure or device reset has occurred.
Configuration Changed – An operation was performed that changed the device’s configuration.
Device Malfunction – The device detected a serious error or failure that compromises device operation.
Table 16 – Command-Specific Response Codes
(Success) No command-specific errors
(Error) Upper Range value too low/Invalid mode
(Error) Invalid selection/Invalid Poll Address
(Error) Upper and Lower Range values out of
limit
(Error) Passed parameter too large
(Warning) Span too small/Status byte mismatch
(Error) Passed parameter too small
(Mode Error) Access restricted
(Error) Too few data bytes received
(Error) Invalid units code
(Misc Error) Device-specific command error
(Mode Error) In Write-Protect mode
(Error) Command response truncated
(Error) Invalid date code/Configuration change
counter mismatch/Lower range value too
high/Incorrect loop current mode or value
(Error) Lower Range value too low
(Error) Command not implemented
(Error) Upper Range value too high/Loop
current not active (device in multidrop mode)