Industrial inductive proximity switch:
principle of operation
inductive:
inductive proximity switch products high frequency altering field at the sensing face. When any metallic material enters in the sensing zone of the switch, the field gets disturbed. A sensitive detector circuit senses this change which is further processed by amplifier circuit to produce output signal.
| switch size | m8 | m12 | m18 | m24 | m30 | m36 | m48 | m70 | block |
| sensing distance flush | 1. 5 | 2. 5 | 4-5 | 6-8 | 10-12 | 13-15 | 12-15 | 20 | -- |
| non flush | -- | 3 | 6-8 | 8-10 | 11-15 | 17 | 15-20 | 30-35 | 15-17 |
object:
the sensing distance specified here is for object made of mild steel, having thickness of 1mm. Size of the object should be at least equal to the diameter of switch/ sensing face. For object other than m s apply suitable correction factorºº
sailent features:
1) repeat accuracy : 0. 02 mm
2) hysteresis : 3-10 %
3) grade of protection : ip67, for block type : ip55
4) enclosure : metallic (nickel – chrome plated brass) / stainless steel / plastic
5) led indication : provided
6) ambient : 60 º c max
7) switching frequency : ac switch : 5 hz
dc switch : m 8 & m 12 : 5 khz
above m 18 : 1 khz
dc switches ac switches
a) supply voltage : 10-30 v dc max ripple :10% 90-230 v ac, 50 hz max surge current : 1 a
b) protection : short circuit and wrong polarity, (except size m8) protection against transients and voltage spikes
c) length : 65mm / 50mm 80 mm
d) logic available : no / nc / changeover no / nc
e) load current : 200 ma / 500 ma (on request) 150 ma, 500 ma (on request), (min 30 ma)
three / four wire dc switches: series: is 3d/ 4d:
these are three / four wire switches (+ ve, -ve and output) working on 10-30 v dc, and directly drives dc relay. Theses switches are compatible with plc modules because of its insignificant leakage current (50 µ a max) dc switches are divided into two categories according to load connection
-
load connected between supply wire and output wire : (npn)
-
load connected between ground wire and output wire: (pnp)
entire range is available with no or nc logic. Special switches with change-over logic are also available. Dc switches are protected against overload, short circuit and wrong polarity connection. Special switches with high operating frequency are available for applications of speed sensing. Special protection incorporated within the switch against back emf from inductive load like relay.