IM_ONE_Safety-07
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13
ADVANCED FEATURES
NOTE:
No initial configuration of these features is required. The default for these advanced commands is zero or off.
Adjusting Display Offset
The One Series
Field Safety System™
is factory calibrated to 0.25% of the sensor’s maximum range at room temperature. In some
installations, it may be necessary to adjust the display’s offset due to the range and position of the sensor. Chemical seals with long
capillaries combined with low maximum range sensors are a common cause of offset error. The OFFSET command allows the user
to enter a positive (“POS”) or negative (“NEG”) offset to the display readings. An offset adjustment of up to +10% of the sensor’s
maximum range is allowed. If adjusting OFFSET, it may be necessary to adjust SPAN (see below).
Example: When the sensor has a zero pressure applied, but the display reads a value other than zero, entering the additive inverse
(reversing the sign) of the displayed value for OFFSET will force the display to read zero.
NOTE:
Any numerical value entered other than 0.00 will cause the display to indicate “Offset” just above the process reading in the
process display.
USE OF THIS OPTION MAY CREATE A CONDITION WHERE THE DISPLAY MAY INDICATE “0.00” WHEN SIGNIFICANT PRESSURE OR
TEMPERATURE (UP TO 10% OF MAXIMUM RANGE) EXISTS IN THE SYSTEM. INDEPENDENT VERIFICATION OF THE PROCESS VARI-
ABLE SHOULD BE DONE PRIOR TO MAINTENANCE ON THE SYSTEM WHEN “OFFSET” APPEARS ON THE DISPLAY.
Refer to the Programming Flowchart on page 19.
• Enter the Programming Mode and use the left
2
button to move to the OFST command.
• Press the right
g
button to select a positive or negative offset. POS is default. Use the left
2
button to change to NEG.
• Press the right
g
button to view and change the offset. Zero is the factory setting. Press the left
2
button to increment the blink-
ing digit. Press the right
g
button to enter and move to the next digit.
• Press the right
g
button to enter the new offset and return to the main menu.
Adjusting Span
SPAN provides an adjustment to shift the slope of the sensor’s response curve to accommodate an offset value other than zero. To
adjust SPAN, calculate and enter a new SPAN value.
To calculate the SPAN value, apply a reference source below maximum scale to the sensor. Record the value that shows on the One
Series
Field Safety System™
display and the reference source value. Divide the reference source value by the display value and then
multiply the result by the sensor’s upper range.
FORMULA: SPAN = reference source / display value x upper range value
• Pressure example: For a sensor range of 0 - 100 psi, choose a reference source (90) below the upper range limit (100) to
prevent an over range condition. Divide the reference source value from the resulting display value (88). Multiply the result by the
upper range limit. Span = 90 / 88 x 100 = 102 (rounded)
• Temperature example: For a sensor range of -40 to 450ºF, choose a reference source (400) below the upper range limit (450) to
prevent an over range condition. Divide the reference source value from the resulting display value (404). Multiply the result by
the upper range limit. Span = 400 / 404 x 450 = 446 (rounded)
Refer to the Programming Flowchart on page 19.
• Enter the Programming Mode (see page 10) and use the left
2
button to move to the SPAN command.
• Press the right
g
button to select a positive or negative span. POS is the default. Use the left
2
button to change to NEG.
• Press the right
g
button to view and change the span. Zero is the factory setting. Press the left
2
button to increment the blink-
ing digit. Press the right
g
button to enter and move to the next digit.
• Press the right
g
button to enter the new span and return to the main menu.
