Rockwell Automation 1797-OE8H FLEX Ex HART Analog Modules User Manual - Manual (Page 87)

Publication 1797-6.5.3 - March 2006
Calibrate Your Module 5-11
1797-IE8H Calibration with Offset and Gain
You must calibrate the offset from a channel before gain is calibrated at the
same channel, because the gain value depends on the offset value. During the
calibration of offset, the corresponding gain value is declared invalid. Before
all values are calibrated, there is a calibration error displayed within the Real
Time Data in the diagnostic status. After calibration is complete, the calibrated
values are stored in the RAM area by the I/O module. Therefore, a store
command is necessary to cause the I/O module to transfer the RAM content
to the EEPROM.
Use the following guidelines when setting the offset and gain calibrations:
• To calibrate a channel according to offset, the corresponding channel
must be sorted, or opened, so that flow is 0.00 mA.
• To calibrate a channel according to gain, the corresponding channel
must be supplied with 20.00 mA.
• Set the I/O module ambient temperature in the range of 25…±5 °C.
• Check the calibration status to see if it is idle or erroneous before
sending the calibration command by reading attribute 67
hex
.
Calibration Command
Given Back by the I/O Module Indicates
Idle or erroneous Calibration is complete
Pending Poll the status again and recheck
Does not correspond with the first written
command Access conflict with another calibration
device or another access error — repeat
the calibration command
Idle and it corresponds with the first written
command Successful calibration by the module