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This type sheet contents the essential details of the deliverableversions of inductive limit switches with explanations to the switching functions and the electrical connections.
Detailed notes on the mode of action and application of electromechanical, inductive and pneumatic limit switches is presented in our overview 1100.1110.
Switching functions
Model code I= "inductive limit switch";
Characteristic number 1 = Closing at transgression of the set
value in clockwise direction (opening counter clockwise);
Characteristic number 2 = Opening at transgression of the set
value in clockwise direction (closing counter clockwise)
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| schematic diagram | switching functinos and control behaviour at
indicator movement in
clockwise direction | type / characteristic number |
|---|
| limit switches with one limit value |
 | Öffner ¹) | I 2 |
 | Schließer ²) | I 1 |
| limit switches with two contacts |
 | 1. and 2. limit value
opener ¹) | I 22 |
 | 1. limit value opener¹)
2. limit value closer ²) | I 21 |
 | 1. limit value closer ²)
2. limit value opener ¹) | I 12 |
 | 1. and 2. limit value
closer ²) | I 11 |
¹) Opener:
The control lug is moved by the clockwise indicator movement into the slot initiator. Only a little control current is flowing (≤ 1 mA), the initiator becomes high resistive, the relay in the downstream isolating amplifier drops out on load current principle.
²) Closer:
The control lug is moved by the clockwise indicator movement out of the slot initiator. Again a higher control current is flowing (≥ 3 mA), the initiator becomes low resistive, the relay in the downstream isolation amplifier picks up. |
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The wiring diagrams for limit switches with 3 (or 4) limit values are
available on demand. The switching functions have to be specified
with indicator movement in clockwise direction too.
e.g.:
1. limit value: opener
2. limit value: opener
3. limit value: closer (e.g. I 2.21)
The switchpoints are adjustable from outside through the inspection glass via an adjuster with a loose key.
On pressure gauges with 3 (or 4) limit switches the set point indicators are not all adjustable above each other. Therfore please quote on orders, which indicators must be adjustable about each other (e.g. I 2.21 or I 22.1) respectively where your switchpoints should be.
Electrical characteristics
acc. to DIN EN 60947-5-2 (EMV) respectively DIN EN 60947-5-6 (NAMUR)
Electrical connection
cable box blue, with M20x1,5 cable screw connection with strain relief
The clamps in the cable connection box are numbered according to the wiring diagram.
Special constructions
• quadruple contacts limit switches on demand (limitations due to the necessary der erforderlichen mounting depth)
• double-limit switches with fixed switching distance
• double-limit switches NG 160 in intermittent operation, complete reactionless operation mode, particularly suitable for precusion pressure
gauges cl. 0,6;
The control lug on this special construction resides at the actual value pointer. On utilization of the isolation amplifier KFA6-SR2-EX2.W/IR, that is
specially developed for this limit switch, it is ensured that also at transgression of the adjusted maximal respectively minimal limit values the according switching function is preserved.
The control lug can therefore exceed over the adjusted set value, leaving the slot initiator and also dip in again at recession without changing
the switching behaviour. Also a power blackout causes no change. After re-establishment of the current supply the last active switching position is
restored.
• adjuster with fixed key
• safety version (SN),
applicable in connection with a separation switchgear in safety technology for the building of self-monitoring controls (safety switching).
In case of a failure, whether at the slot initiator or in the isolation amplifier, the initial condition compulsorily becomes "0". The conception of these safety switches was examined by the TÜV and was approved according to the safety requirements for important circuits.
• safety version with inverse direction of action
(S1N)
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We reserve the right to alter technical data.
