Flowline LD32‐S4_1 DeltaSpan - Manual (Page 11)

Rev B MN301040 11 of 16
ELECTRICAL INSTALLATION Step Eight
Wire Length ‐ The maximum length of wire connecting the transmitter and receiver is a function of wire size and
receiver resistance. Wiring should not contribute more than 10% of the receiver resistance to total loop
resistance. For extremely long runs (over 1000 feet), choose receivers with higher resistance to minimize the size
and cost of connecting leads. Where wiring length is under 100 feet, wire as small as 22 AWG can be used.
Wiring ‐ An external power supply delivering 10‐28 VDC with minimum current capability of 40 mA DC (per
transmitter) is required to power the control loop. See Fig. A for connection of the power supply, transmitter
and receiver. The range of appropriate receiver load resistance (RL) for the DC power supply voltage available
is expressed by the formula:
RLmax = (Vsup – 10V) / 20 mA DC
 Shielded cable is recommended for control loop wiring.
 Use the Red wire as the (+) and the Black wire as the (‐).
Fig. A
Wiring – Control Drawing