Basler BE1-59NC, Instruction Manual

3-2 

BE1-59NC Functional Description 

9279400990 Rev B 

The definite time delay is adjustable from 00.1 to 99.9 seconds in 0.1 second increments. Front panel 
mounted switches determine the delay. Position 00.0 is instantaneous. 

Inverse Time Delay 

Inverse time delay circuits are identical to definite time delay circuits except that a voltage controlled 
oscillator (VCO) is substituted for the clock signal. The VCO is controlled by a voltage derived from the 
sensed input. Because the frequency of the oscillator is kept proportional to the sensed input voltage, the 
desired inverse time delay is produced. 

Inverse time characteristic curve thumbwheel switches are settable from 01 to 99 in 01 increments. Each 
position corresponds to a specific curve setting except 00, which is instantaneous. Refer to Figures 1-3 
and 1-4 to see the inverse time characteristic curves. 

Reference Voltage Circuit 

A constant voltage source provides a reference voltage to the potentiometers on the front panel. The 
potentiometers, in turn, provide reference voltages to all the comparator circuits and establish the 
threshold for each circuit. 

Power Supply Status Output 

The power supply status relay has a set of normally closed contacts and energizes when operating power 
is applied to the relay. If relay operating power is lost or either side of the power supply output (+12 Vdc 
or –12 Vdc) fails, the power supply status relay de-energizes and opens the power supply status output 
contacts. 

Power Supply 

Operating power for the relay circuitry is supplied by a wide range, electrically isolated, low-burden power 
supply. Power supply operating power is not polarity sensitive. The front panel power LED and power 
supply status output indicate when the power supply is operating. Power supply specifications are listed 
in Table 1-1. 

Target Indicators 

Target indicators are optional components selected when a relay is ordered. The electronically latched 
and reset targets consist of red LED indicators located on the relay front panel. Latched targets are reset 
by operating the target reset switch on the front panel. If relay operating power is lost, any illuminated 
(latched) targets are extinguished. When relay operating power is restored, the previously latched targets 
are restored to their latched state. 

A relay can be equipped with either internally operated targets or current operated targets. 

Internally Operated Targets 

The relay trip outputs are directly applied to drive the target indicators. The indicators are illuminated 
regardless of the current level in the trip circuits. 

Current Operated Targets 

Current operated targets are triggered by closure of the corresponding output contact and the presence of 
at least 200 milliamperes of current flowing in the trip circuit. 

NOTE 

Prior to September 2007, the BE1-59NC target indicators consisted of 
magnetically latched, disc indicators. These mechanically latched target 
indicators have been replaced by the electronically latched LED targets in use 
today.