Rockwell Automation 1756-OF8H ControlLogix HART Analog I/O Modules - Manual (Page 106)

106 Rockwell Automation Publication 1756-UM533C-EN-P - February 2011
Chapter 7 Configure the Modules with RSLogix 5000 Software
Configure All Channels
Use this table to configure the parameters on the Configuration tab that apply to
all the channels.
Output
Range Chose a value from the
drop-down menu. 0…20 mA or 4…20 mA is required for HART. No
Sensor
Offset Enter a value from
-9,999,999…99,999,999 (float). • The default value is 0.00.
• The offset value is in engineering units.
• The Sensor Offset is added to the data value to determine signal level. No
Hold for
Initialization Check or uncheck • Check this box to cause the module to hold the output signal unchanged
until the output value received from the controller in the ChxData field is
within 0.1% of full scale of the value being held. The output holds when
the following occurs:
– Powerup occurs (holds at zero)
– A new connection is established (brings it out of fault state and it holds
at the fault value from the previous configuration).
– The controller returns to Run mode after Program mode (continues to
hold at the configured value that was held in Program mode, see the
Output State tab).
• The output channel holding lets the controller synchronize with the output,
enables smooth output transitions and avoids rapid transients when
control resumes from an interruption.
• The output can be ramping to the configured hold value when the
transition occurs. In this case, it continues the ramp until it completes or
until the output value from the controller is within the 0.1% of the output
signal. When the Hold for Initialization box is not checked, the output
switches as quickly as possible to the first value commanded by the
controller.
No
Table 25 - Configuration Tab Parameters
Parameter Action Notes Available in
Hard Run Mode?
Table 26 - All Channels Configuration Parameters
Parameter Action Notes Available in Hard
Run Mode?
Keep HART
Replies Select a value from
1 to 255 s. • HART pass-through message replies are kept for this time. HART replies that are
received from the Field Device in response to pass-through messages you have sent are
kept for this long. You must retrieve them within this time or the module discards them.
• The default is 15.
No
Pass through Choose a value from
the pull-down menu. • Determines how often pass-through messages occur.
– Once per two channels scanned (default)- After 2 channels have PVs scanned to the
input tag, a pass-through message is sent (if one is pending).
– Once per module scan - Choose this value if you want to minimize the impact
pass-through message clients have on reading the PVs into the input tag.
– Once per channel scan - After each channel has its PVs scanned to input tag, a
pass-through message is sent (if one is pending). Choose this value if you want to
give pass-through messages from clients such as FactoryTalk AssetCentre higher
priority than reading PV, SV, TV, FV and field device health into the input tag. See the
Pass -through Setting, Ratio, and Priority table on page 107 for more information.
No
IMPORTANT We do not recommend a value of less than 15 s.