Psa-6b, 7b, & 8b, Selection & application of proximity sensors, Psa-6b, 7b, & 8b specifications – Red Lion PSA - INDUCTIVE User Manual

Page 2: Dimensions in inches (mm) psa-6b psa-7b psa-8b, Maximum sensing distance reduction factors, Minimum sensor spacing

+10 to +30 VDC

@ 10 mA max.

PSA-6B, 7B, & 8B

These Inductive Proximity Sensors have a maximum sensing distance of

0.059" (1.5 mm), 0.197" (5 mm) and 0.394" (10 mm) respectively, and operate

over a wide power supply range (See Specifications Below). They are each

housed in threaded metal cases and are supplied with 2 metal jam nuts for

mounting. The NPN transistor outputs are true open collector and are

compatible with most RLC counter and rate input circuits. Maximum sensing

frequencies are ≤ 3 KHz, 1 KHz, and 500 Hz respectively. In addition, the

outputs are overload and short circuit protected. These sensors are shielded for

flush mounting in metal applications.

PSA-6B, 7B, & 8B SPECIFICATIONS

In addition to the coil and oscillator circuit, the 3-wire Models PSA-6B, 7B,

and 8B each contain a Detector Circuit and NPN Transistor Output (See Figure

3). In these units, the Detector Circuit senses when the oscillator stops, and

turns on the Output Transistor which controls the load. The Detector Circuit

also turns on an integrally case mounted L.E.D., visually indicating when a

metal object is sensed.

DIMENSIONS In inches (mm)
PSA-6B

PSA-7B

PSA-8B

NOTES:

1. PSA 6B case material = #303 stainless steel.

2. PSA 7B & 8B case = chromed brass.

3. PVC Cable Jacket.

SELECTION & APPLICATION OF PROXIMITY

SENSORS

Selection of the proper proximity sensor depends on the size, material, and

spacing of the target being sensed and the sensing distance that can be

maintained. The maximum sensing distance is defined as the distance in which

the sensor is just close enough to detect a ferrous target whose diameter is equal

to or greater than the sensor diameter. In actual application, the sensing distance

should be between 50 to 80% of the maximum sensing range to assure reliable

detection. For target sizes smaller than the sensor diameter, the maximum

sensing distance can be estimated from the curve (See Figure 4). A further

reduction factor must also be applied if the target material is non-ferrous metal

(See Figure 5). Ideally, spacing between adjacent targets should be at least one

sensor diameter so that the first target completely leaves the sensors field before

the next target appears. Individual targets can still be resolved as separate

objects if this spacing is reduced to 70 or 75% of the sensor diameter, however,

this can introduce a minimum limit on sensing distance that makes adjustment

more critical. All Proximity sensors are internally shielded which allows the

sensor face to be flush mounted in metal applications without reducing sensing

distance. In applications where proximity sensors must be placed next to each

other, a distance of at least 1 sensor diameter should separate sensors to

eliminate any frequency interference (See Figure 6).

METAL TARGET

CIRCUIT

OSC.

COIL

PSA 6B, 7B, or 8B

+VDC

COMMON

OUTPUT TRANSISTOR

OUTPUT

DETECTOR

LED

Figure 3

LED

.51 (13) ACROSS FLATS

.16 (4) THICKNESS

.315

1.64 (41.6)

6.56' (2 METERS)

#24 AWG

3-CONDUCTORS

1.57 (40)

(8)

M8 X 1

(ISO 68 METRIC

STRAIGHT THREADING)

LED

.94 (24) ACROSS FLATS
.16 (4) THICKNESS

.708

2.13 (54)

6.56' (2 METERS)

#20 AWG

3-CONDUCTORS

1.97 (50)

(18)

M18 X 1

(ISO 68 METRIC

STRAIGHT THREADING)

LED

1.42 (36) ACROSS FLATS

.19 (5) THICKNESS

1.181

2.52 (64)

6.56' (2 METERS)

#20 AWG

3-CONDUCTORS

2.37 (60)

(30)

M30 X 1.5

(ISO 68 METRIC

STRAIGHT THREADING)

MAXIMUM SENSING DISTANCE REDUCTION FACTORS

Reduction in the max. sensing distance
due to decrease in diameter of ferrous
targets.

Figure 4

Typical reduction factors for various non-
ferrous targets with diameters equal to or
greater than sensor diameter.

Figure 5

100%

APPROX. 65%

APPROX. 60%

APPROX. 50%

APPROX. 40%

MILD STEEL

STAINLESS

MERCURY

LEAD

BRASS

STEEL

MATERIAL

% SENSING DISTANCE

Nominal sensing range x % sensing

distance = actual sensing range

APPROX. 25%

APPROX. 30%

COPPER

ALUMINUM

.25

.75

100

% OF MAX. SENSING DISTANC

RATIO,

SENSOR DIAMETER

TARGET DIAMETER

MINIMUM SENSOR SPACING

Figure 6

Note: PSA-6B, 7B, and 8B outputs are NPN open collector outputs. A

PSA-6B, 7B, or 8B may be used as an input to more than 1 indicator or

control only if the respective power supplies of each unit are

“unregulated” and can load share. It is recommended to use only one

power supply for sensor power. An indicator or control with a regulated

power supply may not be paralleled.

Counter #1 and #2 both contain

unregulated +12 VDC Power

Supplies.

1 x D

1 2 3

LO FR

LO BIAS

LO FR

1 2

* APPLICATION

DEPENDENT

* APPLICATION

DEPENDENT

TYPICAL COUNTER

INPUT SWITCH SET-UP

TYPICAL COUNTER

NPN OPEN

COLLECTOR

PSA 6B, 7B, or 8B

+VDC

OUTPUT

COMMON

COUNTER #2

COUNTER #1

+12V

COMM.

CNT.

COMM.

+12V

PSA-6B

PSA-7B

1. Power Supply:

+10 to +30 VDC

@ 10 mA max.

REVERSE POLARITY PROTECTION

≤ 3 KHz

1 KHz

500 Hz

3. Output:

NPN Open Collector Output,

Overload and Short Circuit protected.

SAT

= 1.8 V @

200 mA max. load

4. Maximum Sensing Distance:

0.059" (1.5 mm)

0.197" (5 mm) 0.394" (10 mm)

5. Wire Color Code:

Brown = +VDC; Blue = Common; Black = Output

PSA-8B

6. Operating Temperature:

-25°C to +70°C (-13°F to +158°F)

7. Construction:

NEMA 1, 3, 4, 6, 13 and IEC IP 67

2. Maximum Switching Frequency:

SAT

= 1.8 V @

150 mA max. load