SOR Single Point Ultrasonic Level Switch - Manual (Page 6)

6/20 Form 771 (08.13) ©SOR Inc.
Electrical Connection (Remote Self-Test)
Ensure that wiring comforms to all
applicable local and national
electrical codes and install unit(s)
according to relevant national and
local safety codes.

Make sure the power source is
turned off.

Remove the housing cover.
Explosion Proof and Non-Agency Listed models:
TB2 Remote Self-Test Terminal Block
(Non-Intrinsically Safe Units Only)
TB1
Loop Power Terminal Block
Remote Dry Contact Ground Twisted Pair Shield
to Housing Ground Screw
1800
1700
1600
1500
1400
1300
1200
1100
1000
900
800
700
600
500
400
300
200
100
0
Power Supply Voltage (Volts)
5 10 15 20 25 30 35 40
Maximum Loop Resistance (Ohms)
(including Barrier Resistance)
Loop Resistance vs. Power Supply Voltage
1 Ohm at
11 VDC
850 Ohms
at 28 VDC
650 Ohms
at 24 VDC
950 Ohms
at 30 VDC
1450 Ohms
at 40 VDC
Electrical power must be disconnected from explosion proof models before
the cover is removed. Failure to do so could result in severe personal injury
or substantial property damage.

Pull twisted pair cable through the conduit connection and into the control housing.

Connect dry contact wires to TB2 on the control board. (See ) Terminals are
labeled “RMT COM” and “RMT TST*”. Attach the twisted pair shield to the ground
screw inside the housing. Ground only one end of the twisted pair shield.

Do not apply power to the remote test terminals.

Connect the open end of the wires to a dry (unpowered) contact designed for small
loads. There is no polarity required for this connection.