SMI30 Datasheet, PDF (2/6 Pages) List of Unclassifed Manufacturers – Intrinsically Safe Sensors

SMI30 Series Intrinsically Safe Sensors
SMI30 Series receivers have a red LED alignment indicator that lights
whenever the receiver "sees" its modulated light source. Emitters have
a red LED to indicate "power on". All LED indicators are mounted
internally to preserve the waterproof integrity of the sensor housing, and
are visible from both the side and front of the sensor through the sensor's
quad-ring sealed acrylic lens.
The innovative circuitry used in SMI30 Series emitters and receivers
provides the best noise immunity of any self-contained opposed mode
sensor pair. For applications where optical crosstalk between sensors
might be a problem, SMI30 Series emitters and receivers are available
with a choice of three modulation frequencies (frequency "A",
frequency "B", or frequency "C"). This makes it possible to use high-
powered sensor pairs of different frequencies in close proximity to
each other without crosstalk. (NOTE: frequency "A" is standard;
frequencies "B" and "C" are available by special order. An emitter and
its receiver must be of the same modulation frequency.) See the chart
on page 5 for a summary of models.
Each unit is supplied with two hexagonal jam nuts. A 30mm clearance
hole is required for mounting, and mounting bracket models
SMB30MM, SMB30S, and SMB30C are available (page 6). All
models have a built-in standard quick-disconnect ("QD") connector.
"QD" models mate with 12-foot long model SMICC-312 or 30-foot
long model SMICC-330 mini-type QD cable (sold separately from
sensor).
SMI30 Series
Dimensions
PVC-covered
mini-type QD cable
MBCC Series QD Cable (order separately)
SMICC-312 (12 feet, p/n 36356) or SMICC-330 (30 feet, p/n 36357)
3-wire QD cable for emitters and receivers
Sensor end (male connector) Cable end (female connector)
Hookup Information
SMI30 Series sensors are certified intrinsically safe ONLY
when used with certified energy-limiting intrinsically safe
barriers. Emitter units use a two-wire hookup (there is no output
connection). Note from the hookup diagram (page 3) that the
receiver installation may be made using either a single barrier
(2-wire hookup) or with a dual channel barrier (3-wire hookup).
In the 2-wire configuration, the sensor acts as a current sink,
drawing less than 10mA in the OFF state and more than 20mA
in the ON state. The customer must provide a current sensing
device ("current sensor" in the diagram) to convert the current
to a logic level. SMI30 Series sensors may be used with Banner
Current Amplifier Control Module CI3RC2.
Cable connector (female,
for SMICC cable,
side view)
The CI3RC2 module may be purchased (with model RS-11
module socket, one dual-channel barrier, and DIN rail barrier
mounts included) by specifying kit model CI2BK-2. One dual-
channel intrinsic barrier (alone) may be ordered by specifing
model CI2B-1. See the photo, page 5.
In the 3-wire configuration, the output may be used directly to
control loads of less than 15mA.
In selecting the barrier, it is important to consider the barrier's
resistance. The sensors must have at least 10 volts across the
brown and blue power leads for proper operation, and the
barrier will cause a voltage drop due to its resistance. The
formula that determines how much resistance is allowed is:
R = 40 (supply voltage - 10 volts).
If the supply voltage is 24V dc, then the maximum resistance is
560 ohms. If the supply voltage is 18V dc, then the maximum
resistance is 320 ohms. This includes the resistance of any
current sensing device used (in the 2-wire configuration), so the
barrier resistance must be further reduced by the current sensor
resistance.
Note that, in the 3-wire hookup, the barrier is in series with the
load. This results in an apparent saturation voltage of the output
that is higher than the sensor output by the amount of IxR
(current times voltage) drop through the barrier.
Emitters use the 2-wire hookup; receivers use either 2- or 3-wire
hookup. See the chart (page 5) for a summary of models.
Barriers are generally classified as either "positive input" or
"negative input". SMI30 Series intrinsically safe sensors re-
quire "positive input" barriers for both supply and load. The
blue (negative supply) lead of the sensor is normally connected
to the ground terminal of the barrier.
The user of this equipment is responsible for proper installation
and maintenance of the equipment, and must conform with the
certification requirements relating to barriers and to maximum
allowable capacitance and inductance of the field wiring. If you
are in doubt about these requirements, our applications engi-
neers can refer you to the appropriate authority.
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