Panametrics Sentinel LCT, Руководство пользователя

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Chapter 2. Installation
26 Sentinel LNG User’s Manual
2.4.7 Wiring the 4-20mA Analog Inputs (Optional)
1. Disconnect the main power to the flowmeter and remove the enclosure side cover.
2. Install a cable gland in the chosen conduit hole on the top of the electronics enclosure and feed a standard
twisted-pair cable through this conduit hole.
3. Locate the 26-pin terminal block (TB2) in Figure 27 on page 34, and wire the I/O terminal as indicated on the label
inside the wiring access cover (see Figure 10 on page 20, Figure 27 on page 34 or Figure 28 on page 35.
4. Secure the cable clamp.
WARNING!
To meet CE Mark requirements, all cables must be installed as described in Appendix B,
CE Mark Compliance .
5. If wiring of the unit has been completed, reinstall the side cover on the enclosure and tighten the set screw.
The analog input option provides either three isolated 4-20mA analog inputs, or two isolated 4-20mA analog inputs
and one RTD input (designated Ain1, Ain2, Ain3 and RTD1). Each of the 4-20 inputs includes a 24 VDC power supply for
loop-powered transmitters. The inputs may be used to process temperature, density and pressure signals.
Note: To enter programming data during operation of the
Sentinel LNG
, it will be necessary to know which input is
assigned to which process parameter. This information should be entered in Appendix C, Data Records .
The analog inputs, which have an impedance of 118 ohms, should be connected with standard twisted-pair wiring.
Power to the transmitter may be supplied either by the internal 24 VDC power supply on the analog input terminal or
by an external power supply. Figure 17 on page 27 shows typical wiring diagrams, with and without an external power
supply, for one of the analog inputs. Figure 18 on page 27 shows 4-wire RTD input wiring. Wire the analog inputs as
shown on the label in the enclosure side cover (see Figure 10 on page 20 and Figure 26 on page 33). Terminal
locations are shown in Figure 19 on page 28 through Figure 22 on page 29.
It is recommended to use 12-24 AWG (3.3 - 0.2 mm
2
) for single conductor wiring, and 16-24 AWG (1.5 - 0.2 mm
2
) for
two conductors per terminal.