United Electric Controls ONE Series, Инструкция по установке и обслуживанию

Страница: 11 / 32

Theory of Operation
The One Series electronic switch evaluates the measured process variable and switches the
output ON or OFF based on the set point & deadband values, and the selected switch mode.
Programmable features such as set point, deadband and switch mode determine how the product
is to operate and at what values.
n The SET POINT is the value at which the output switch turns ON or OFF to initiate
an alarm or shutdown sequence. See Setting of User Parameters - Set Point.
n The DEADBAND setting determines the difference above or below set point at which
the output switch will reset after the set point has been reached. See Setting of User
Parameters - Deadband.
n The SWITCH MODE setting determines if:
o
The switched output is ON or OFF above or below the set point value
(NO or NC).
o
The local LED status indicator flashes to indicate the switch output has tripped
either above or below the set point value.
o
The I Am Working (IAW™) signal pulses either above or below the
set point value.
o
The deadband is above or below the set point value. See Setting
of User Parameters - Switch Mode.
n The - Extreme and + Extreme stored by the One Series are the minimum and maximum
process values (lowest and highest) sensed by the product. This provides a snapshot of
process variations since the last time these values had been reset by the user.
A local status indicator (LED) aids the user in determining the switch output state. When the LED
is illuminated continuously, it signifies normal operation (no fault condition). A flashing LED
signifies a tripped condition (an alarm or shutdown condition, process variable has surpassed the
set point value). If the LED is not illuminated, it signifies the switch has lost power or is not able
to function properly. Whether the LED output is ON above or below the set point is determined
by the SWITCH MODE setting.
I Am Working (IAW™) signal provides a remote signal which can be used to determine the
"health" of the product. It can also be used to determine whether the output has tripped.
The IAW™ signal has three (3) states:
n ON when the product is powered, and internal diagnostics determine
that it is functioning properly and the output has not tripped.
n OFF when product has lost power or the internal diagnostics have indicated a failure.
n Flashing ON and OFF (in 50 mS. intervals) to indicate that
the product is functioning properly but the output has tripped.
The IAW™ output is an open drain (collector) output which may be used as a signal to a PC, PLC
or DCS logic input or to drive a 5 to 30 VDC (100 mA max.) load. The internal diagnostics test the
"health" of the microprocessor, sensor, firmware and power supply for proper operation.