B&B Electronics ISOCON-3 - Manual - Manual (Page 14)

ISOCON-3 USERS GUIDE
When the unit is used to convert a thermocouple input it is important when
calibrating to ensure that the thermocouple simulator employed is switched to
automatic cold junction compensation and is at the same ambient temperature as
the ISOCON. Note that this is not always easy to achieve, especially if the
ISOCON is mounted in a warm cabinet. An altenative method is to use an ice-
point reference and a mV source.
6. INSTALLATION
The ISOCON’s input and output circuits are classed as Separated Extra Low
Voltage (SELV). This means that they must not be externally connected to
voltages exceeding 30V ac or 60V dc, nor do they generate voltages above these
limits internally. Where a higher voltage input is required a specially designed
DIVIDER unit can be used to condition the input signal prior to connection to the
process input terminals.
The ISOCON unit clips directly onto ‘Top Hat’ (TS35) symmetrical DIN rail.
Ideally, mounting orientation should be vertical, with the power supply situated
on the top face to minimise temperature rise. Good airflow around the unit will
maximise reliability of the instrument.
The use of bootlace ferrules is recommended on wiring terminations.
Do not exceed terminal torque rating of 0.4 Nm – use an appropriate screwdriver.
The unit can be removed from the DIN rail by sliding a small screwdriver into the
slot at the rear of the enclosure on the lower face and gently levering the metal
clip, whilst lifting the unit from the rail.
Although the unit is protected by a non-resettable internal fuse, it is essential that
the following provisions are made in the installation:
An anti-surge fuse with a voltage rating of 250V ac and a breaking capacity of
35A at 250V ac shall be wired in series with the supply live conductor (terminal
2). For 230V supplies T32mA should be used and for 115V supplies T63mA
should be used. An appropriately marked or labelled switch or circuit breaker
meeting the requirements of IEC947-1 and IEC947-3 shall be included in the
supply installation in close proximity to the equipment, within easy reach of the
operator. The supply neutral (terminal 1) should be connected to the mains
supply neutral.
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14 IIG-060901