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2.2.
Non-incendive and Intrinsically Safe [ic] Inputs and
Outputs
If a specific connection is rated non-incendive (NI) for Division 2 or intrinsically safe [ic] for Zone
2/22, then a list of the field circuit parameters or entity values for that connection will be given on
the control drawing or certificate. If an approved apparatus will be connected to a non-incendive or
intrinsically safe [ic] connection, then a comparison must be made between the electrical field
circuit parameters or entity values of both devices including the connecting cable. These field circuit
parameters or entity values include voltage, current, capacitance and inductance. Power is not
required in the comparison of a Division 2 or Zone 2/22 non-incendive or intrinsically safe
application.
The two devices must compare as follows in order for the wiring to be considered non-incendive:
The field circuit parameters or entity values associated with the IND570xx terminal are underlined in
the above formulas. The other parameters are related to the other approved apparatus or the
connecting cable.
If any of the above conditions are not true, then the circuit must be treated as an incendive or non-
intrinsically safe connection and protected accordingly. If the parameters compare favorably as
shown above, then no special protection is required for the wiring. Always refer to the electrical
regulations for the country of installation for specific wiring requirements.
2.2.1.
Analog Load Cell
The analog load cell connection is rated non-incendive and intrinsically safe [ic] on the IND570xx
terminal. The non-incendive field circuit wiring (NIFW) and intrinsically safe [ic] entity parameters
are listed here:
2.2.2.
Discrete I/O – Solid State
30205321
|
02
|
05/2017
U
or V
(Maximum voltage permitted) ≥
i
max
I
or I
(Maximum current permitted) ≥
i
max
C
(Input capacitance) + C
(Cable capacitance) ≤
i
cable
L
(Input inductance) + L
(Cable inductance) ≤
i
cable
THE ACTIVE/PASSIVE SLIDE SWITCH ON THE DISCRETE I/O OPTION BOARD MUST NEVER BE MOVED
WHILE POWER IS APPLIED TO THE IND570XX. FAILURE TO DO SO COULD RESULT IN BODILY HARM
AND/OR PROPERTY DAMAGE.
METTLER TOLEDO IND570xx Division 2 and Zone 22 Installation Manual
U
or V
(Total voltage output)
o
o
I
or I
(Total current output)
o
sc
C
or C
(Allowable capacitance)
a
o
L
or L
(Allowable inductance)
a
o
NIFW/Entity
V
/u
= 10.5 VDC
oc
o
I
/I
= 304 mA
sc
o
C
/C
= 1 µF
a
o
L
/L
= 0.6 mH
a
o
WARNING
2-5
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