KHA6-SH-Ex1 Safety Signal Guide: Dry Contact and SN/S1N Sensor Monitoring with Line Fault Detection

Pepperl+Fuchs KHA6-SH-Ex1 is a one-channel switch amplifier for transferring safety-related digital signals from a hazardous area to the control side. It accepts approved dry contacts or SN/S1N proximity sensors and continuously monitors the field circuit for lead breakage and short circuit conditions.

The module uses an 85 to 253 V AC supply, making it suitable for cabinets where an AC-powered isolated barrier is required. Its separate signal and fault outputs help the control system distinguish a normal process change from a wiring problem.

One Input, Three Output Functions

• Output I: Relay signal output used for safety applications up to SIL 3 when the complete loop and documentation meet the required conditions.

• Output II: Additional relay signal output for the selected control arrangement.

• Output III: Passive electronic fault output for lead breakage or short-circuit indication.

The response delay is specified at no more than 1 ms. The module also provides front LEDs so technicians can compare field state, relay behavior, and fault indication during testing.

Dry Contacts Need the Correct Resistor Network

An SN/S1N proximity sensor provides the expected current behavior directly. A mechanical contact requires the resistor arrangement defined by Pepperl+Fuchs: a 10 kohm resistor across the contact and a 1.5 kohm resistor in series.

Without the correct network, KHA6-SH-Ex1 may interpret the loop as a line fault rather than a valid open or closed contact. Before replacing the amplifier, inspect these resistors, terminal tightness, cable continuity, and field-device condition.

Safety Maintenance Focus

For a SIL-related loop, confirm which relay terminals perform the safety function and follow the current safety manual. The sensor, wiring, KHA6-SH-Ex1, output contacts, logic solver, proof-test interval, and final element must be reviewed as one complete safety function.

During a functional test, verify:

1. Normal sensor or contact switching

2. Lead-break detection

3. Short-circuit detection

4. Relay de-energization under a fault condition

5. Fault output and control-system alarm response

6. Correct recovery after the field fault is cleared

Ordering Details

Send the exact model KHA6-SH-Ex1, quantity, destination, delivery deadline, field sensor or contact type, and a photograph of the product label. For a safety replacement, also include the existing terminal drawing and required SIL or performance level.

Other hot sales models for your reference.

KFD2-SH-Ex1, KFA6-SR2-Ex1.W, KFA6-SR2-Ex2.W, KFD2-SR2-Ex1.W, KFD2-SR2-Ex2.W, and KFD2-SR-Ex1.4S.LK.

KFD2-DWB-Ex1.D, KFU8-DWB-1.D, KFD2-EB2, KFD2-EB2.R4A.B, KFD0-SD2-Ex1.1045, and KFD2-RSH-1.2E.L3.

KCD2-SR-Ex1.LB, NJ2-12GK-SN, NJ8-18GK-SN-10M, NJ5-18GK-SN, and NJ4-12GK-SN.

Related Pepperl+Fuchs Safety Interface Models