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FW-F018-P-M_v0404_01_EN.docx
4.6.5
TERMINAL 9-10: POWER SUPPLY BACKLIGHT - TYPE ZB (OPTION)
To power the backlight, a voltage in the range 20-30V DC has to be connected.
Maximum current 30mA. Connect the "
-
" to terminal 9 and the "
+
" to terminal 10.
Fig. 22: Terminal connections - Backlight (ZB).
4.6.6
TERMINAL 11-12: ANALOG OUTPUT LOOP POWER
– TYPE AH
An isolated passive 4-20mA signal proportional to the calculated flow rate is available with this
option. When the output is disabled, a 4.0mA signal will be generated on these terminals.
Please note that terminals 11 and 12 are polarity insensitive.
Fig. 23: Terminal connections - Isolated passive 4-20mA signal.
4.6.7
TERMINAL 11-12: HART COMMUNICATION
– TYPE CR (OPTION)
The F018-P is suitable for connecting a HART master device. This HART master device is
connected to terminals 11 and 12 to enable HART communication with the F018-P.
Fig. 24: Terminal connections - HART communication.
HART Hand-Held device
Most HART hosts/DCS systems have an internal loop resistor (impedance) so a handheld can be
connected anywhere in the loop, in parallel with a device (e.g. over terminals 11 and 12 of the
F018-P), without disconnecting any terminals.
When the resistance of the loop is less than 120 ohm, a resistor has to be added in the loop. This
typically happens when the F018p is powered directly from a power supply and is only connected to
via a Hand-Held device. Typical loop resistance inserted by HART hosts/DCS systems is 250 ohm.
Please consult Appendix C: Hart Communication for more information regarding the HART interface.
