Distance Measurement - Honeywell RM640 Handbook

RM640
• Push [ ] or [ ] to set the screen to "Yes" and push [^ ^ ^ ^ ].
i The output is set to point-to-point mode. The current output changes to a range of 4...20 mA
or 3.8...20.5 mA (this range is set in menu item C4.1.4 Current Out. Range).

6.4.4 Distance measurement

The device gives a current output signal that is related to distance measurements when the
menu item C4.1.1 Current Out. 1 Var. (Current Output 1 Variable)
The display screen of the device can show distance measurement readings if one or more of the
"Value Variable" menu items in the C6.4 1st Measurement Page or C6.5 2nd Measurement Page
menu are set to "Distance".
Menu items related to distance measurement are:
• Current output 1 menu (C4.1)
• Tank Height (C1.2)
• Blocking Distance (C1.5)
• Reference Offset (C1.10)
• Display readings in Normal mode: Display readings in Normal mode: Display readings in Normal mode: Display readings in Normal mode: 1st Meas. Page (C6.4) menu
• Display readings in Normal mode: Display readings in Normal mode: Display readings in Normal mode: Display readings in Normal mode: 2nd Meas. Page (C6.5) menu
The flange facing is the reference point for distance measurement (0 m / 0 ft / 0¨). The position of
the measurement scale (specified by the 0% Range and 100% Range settings) is related to this
reference point. If you configured a measurement scale for the current output signal in the C4.1
Current output 1 menu, you can use a "standard scale" or a "reversed scale". On the standard
scale, the 0% Range measurement value agrees with an output of 4 mA and the 100% Range
measurement value agrees with an output of 20 mA. On the reversed scale, the 0% Range
measurement value agrees with an output of 20 mA and the 100% Range measurement value
agrees with an output of 4 mA.
You can change the reference point from which distance is measured. Use this menu
item:
• Reference Offset (C1.10)
INFORMATION!
Menu item C1.10 Reference Offset Menu item C1.10 Reference Offset Menu item C1.10 Reference Offset Menu item C1.10 Reference Offset
If you move the reference point above the flange, make sure that you add the value given in menu
item C1.10 Reference Offset when you give a distance for the C4.1.2 0% Range and C4.1.3 100%
Range settings. If you move the reference point below the flange, subtract the value given in
menu item C1.10 Reference Offset when you give a distance for the C4.1.2 0% Range and C4.1.3
100% Range settings.
CAUTION!
If C4.1.1 Current Out. 1 Var. is set to "Distance" and C4.1.2 0% Range (standard scale) is set in
the blocking distance, then the device will not be able to use the full current output range.
34-VF-25-131 iss.1 GLO Feb 2019 US
C4.1.1 Current Out. 1 Var. (Current Output 1 Variable) is set to "Distance".
C4.1.1 Current Out. 1 Var. (Current Output 1 Variable) C4.1.1 Current Out. 1 Var. (Current Output 1 Variable)
www.honeywellprocess.com
OPERATION
6
105