Rockwell Automation 1794-IE8H, Series B FLEX I/O 8 Input Hart Analog Module Installation Instructions - Manual (Page 28)

28 FLEX I/O 8 Input HART Analog Module
Publication 1794-IN108D-EN-P - January 2014
HART Rebuild Bit The HART Rebuild bit will trigger a HART Rebuild on a transition from 0
to 1. The HART Rebuild bit must remain 1 for HART communications to
function after the rebuild completes. If the HART Rebuild bit is set to 0,
HART communications are disabled.
HART Rebuild Flag During the time the system is rebuilding the HART table, the HART
rebuild flag is set.
Range: 0 = normal, 1 = HART rebuilding
HART
Communication
Fault When this bit is set (1), it indicates that HART communications are
failing on the associated channel.
Range: 0 = normal, 1 = HART communication fault
HART Read Back The HART read back bits show deviations between the analog
measured current value on a loop (by the 1794-IE8H) and the digital
current (sensed by the HART device on its own) received by the
1794-IE8H during HART communication in the background. This
functionality can be turned on by defining a HART read back threshold
greater than 0. This functionality is used to recognize loop errors
whereby a parasitic current is bypassing the 1794-IE8H.
Range: 0 = normal, 1 = HART read back threshold is exceeded.
HART Read Back
Threshold Delivers the percentage value (in steps of 1%) of the threshold for
forcing the HART read back indication (input signal deviation
HART/Analog) with a 31% maximum deviation.
If there is no HART transmitter on the loop or the loop is not in the
transmitter list, the function is switched off internally in the I/O module.
Range: 0 = disabled, 1…4 = not supported from I/O module (set to 5
internally), 5…31 = percentage threshold data (5…31%).
HART
Communication Range: 0 = normal, 1 = HART communication is currently occurring.
HART Transmitter
List When this bit is set (1), it indicates that a HART field device was found
during the rebuild sequence on the associated channel.
Range: 0 = transmitter was not found, 1 = HART transmitter was found.
Square Root
Threshold This setting affects all channels using Data Format 2 or 6. It sets low,
end-of-scale percent value at which square roots start being reported.
Below this level 0% is reported. This compensates for asymptotic
values of the square-root function as the input approaches 0.
Range: 0 = disabled, 1 = 2%, 2 = 5%, 3 = 10%
Field Descriptions