300-R010-45G Datasheet, PDF (10/36 Pages) Magnetrol International, Inc. – Echotel® Model 300/301 Ultrasonic Non-Contact Transmitter For Level/Volume/Open Channel Flow

WIRING cont.
OUTPUT SIGNAL WIRING cont.
RS-485 Output
A shielded twisted pair should be used for the RS-485 wiring.
The “A” and “B” connections are made at the terminal block
to the right of the 16-button keypad as shown in Figure 5 on
page 8. The shield is connected with a female disconnect to
a connector located in the housing base, just below the sen-
sor connections.
1. Cut approximately 8" of insulation off the twisted shield-
ed cable.
2. Cut the shield wire down just short enough to crimp a
female disconnect (Sta-Kon^®) connector. Crimp the con-
nector on and push this over the male connector locat-
ed at the base of the housing as shown in Figure 7.
NOTE: If both the 4-20 mA and the RS-485 outputs are
being used, twist the shields together and follow Step 2
above.
3. The “A” and “B” wires should then be twisted together
and run up to the RS-485 terminal block located to the
right of the 16-button keypad as shown in Figure 7.
4. Connect the “A” wire from the control room converter to
the terminal marked “A” on the RS-485 terminal block
located to the right of the 16-button keypad as shown
in Figure 5.
5. Connect the “B” wire from the control room converter to
the terminal marked “B” on the RS-485 terminal block
located to the right of the 16-button keypad as shown
in Figure 5.
6. If connecting multiple Model 300/301 units in a daisy-
chain configuration, be sure to connect the wiring in
parallel and have the ending unit with the termination
resistor jumpered. Jumpers should be removed from
other units in the daisy chain. The three termination
jumper pins (JP1) are located behind the black protec-
tive cover and just below the RS-485 terminal block.
The last unit in the daisy chain should have a jumper
between pins 1 and 2. All other units in the daisy chain
should either have a jumper between pins 2 and 3, or
have no jumper at all.
NOTE: Polarity among units in loop must be observed.
NOTE: If connecting several units, note the color wire used
for A and B and ensure that the same designated color is
used for each of the units.
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