Rockwell Automation 1794-OF8IH FLEX Isolated Input/Output HART Analog Modules User Manual

Page 117

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Publication 1794-UM065B-EN-E - September 2010

Additional HART Protocol Information 105

The second byte of this response code returns the operating status of HART
field devices. This byte may default to 0 when a communications error occurs
as indicated by bit 7 of the first byte being set.

IMPORTANT

The

The host processor ignores any values in the data field when a
communications error is detected.

HART Protocol – Communication Error Code

Bit

Error Code

Description

7

Communications Error

If set, the field device has detected a communications error. Bits 0…6 indicate the type of error.

6

Vertical Parity Error

The parity of one or more of the bytes received by the HART field device is incorrect.

5

Overrun Error

At least one byte of data in the receive buffer of the HART field device was over-written before it
was read.

4

Framing Error

The stop bit of one or more bytes received by the HART field device was not detected.

3

Longitudinal Parity Error

The longitudinal parity calculated by the HART field device does not match the longitudinal parity
byte at the end of the packet.

2

Reserved

Set to 0.

1

Buffer Overflow

The packet is too long for the receive buffer of the HART field device.

0

Undefined

Not defined.

HART Field Device Error Codes

Bit

Error Code

Description

7

Field Device Malfunction

An internal hardware error or failure has been detected by the HART field device.

6

Configuration Changed

A write or set command has been executed by the HART field device.

5

Cold Start

Power has been removed and reapplied, resulting in the reinstallation of the setup information.
The first HART command to recognize this condition automatically resets this flag. This flag may
also be set following a master reset or self test.

4

More Status Available

More status information is available and can be read using command #48. Read additional status
information.

3

Primary Variable Analog
Output Fixed

The analog and digital outputs for the primary variable are held at their requested value. They
will not respond to the applied process.

2

Primary Variable Analog
Output Saturated

The analog and digital outputs for the primary variables are beyond their limits and no longer
represent the true applied process.

1

Nonprimary Variable Out of
Limits

The process applied to a sensor, other than that of the primary variable, is beyond the operating
limits of the device. To identify the variable, use command #48, read additional status
information.

0

Primary Variable Out of
Limits

The process applied to the sensor for the primary variable is beyond the operating limits of the
device.

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