Elcon HiD 2000 Series, User Instruction Manual

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5.16 HiD 2877/2878
Functional description
Energises intrinsically safe solenoid valves, alarm sounders, displays or LED indicators in a Hazardous Area
controlled by a Safe Area contact, transistor or logic-level signal.
Line faults (open or shorted) can be detected and signalled by LED and fault output signal. Status of each channel
is signalled by an LED.
Model 2877 Model 2878
Application Guidelines
The unit function in Bus powered mode with control input that can be a voltage free contact, open collector or logic
level. The voltage free contact or open collector are referenced to supply line while the logic level is fully floating
with in respect to power supply. The unit transfers the input signal in the hazardous area where it is typically used
to drive solenoid valves or audible alarms. The input/output relationship is fixed and is contact close or open
collector close/valve energised or logic level high/valve energised, which correspond the yellow status LED “lit”.
To verify the compatibility of the unit with the solenoid valve, you must have the minimum excitation current I
min
,
the maximum coil resistance R
coil
over the full operating temperature range and the voltage drop V
drop
across the
reverse polarity system if any. Calculate the working voltage by the formula V
work
= I
min
R
coil
+V
drop
and check that
voltage at the specified current value I
min
is below the output characteristic diagram.
A separate fault output is signalled in case of field wiring shorted or opened. The segnalation is done by an fault
red LED “lit” when fault is present, and with common fault bus to de-activate the optional fault monitor module on
termination board. The line fault detection circuit is always active (with valve energised or not energised) and
when used with electronic valve an external paralleled resistor (typically 4.7 K
Ω
) must be applied to the output
terminals, close to valve, to prevent abnormal fault segnalation. Contact Elcon for more details. To prevent fault
segnalation on spare channel/module is necessary to connect a 4.7 K
Ω
½ W resistor across the valve output
terminals 1-4 and/or 2-5.
The unit can be used with all Elcon standard termination board.