Flowline LU78 EchoSwitch - Manual (Page 5)

Rev A MN300282 5 of 34
SAFETY PRECAUTIONS (cont.) Step Three
Make a Fail‐Safe System: Design a fail‐safe system that accommodates the possibility of switch and/or power
failure. FLOWLINE recommends the use of redundant backup systems and alarms in addition to the primary
system. Adding a redundant high level float switch to the system is a cost effective means to prevent costly
tank overflows.
The switch has (3) relay channels. Normally open (NO) or normally closed (NC) operation is user selected
based on the desired system control and fail‐safe logic when the ultrasonic instrument losses its return signal
due to situations such as foam or condensation in the tank. Always design a fail‐safe system that
accommodates for the possibility of functional and/or power failure to the instrument. The "normal" relay
state is where the relay coil is de‐energized and the relay indicator is OFF. Therefore, if power is cut OFF to the
switch it will de‐energize the relay. Make sure that the de‐energized state is the safe state in your system
design. As such, if switch power is lost, a pump will turn OFF if it is connected to the normally open side of the
relay.
Flammable, Explosive or Hazardous Applications: EchoSwitch® should not be used within classified
hazardous environments.
Components: EchoSwitch® is offered in three different models. Depending on the model purchased, you may
or may not have been shipped all the components shown below.
 EchoSwitch®
P/N Max. Range Dead Band Enclosure Thread
LU74‐5004
LU74‐5064
18.0’ (5.5m) 8” (20cm) Type 4X
2” NPT
2” G
LU77‐5004
LU77‐5064
9.8’ (3m) 4” (10cm) Type 4X
1” NPT
1” G
LU78‐5004
LU78‐5064
26.2’ (8m) 8” (20cm) Type 4X
2” NPT
2” G
 Viton® Gasket
o Part #200128 for LU77 series
o Part #220129 for LU74 or LU78 series
 Quick Start Guide