Pepperl+Fuchs WE77/Ex-2 Isolated Switch Amplifier

페펄+푹스 WE77/Ex-2 Installation & 배선 가이드

WE77/Ex-2: Dual-channel NAMUR isolated switch amplifier (intrinsically safe barrier). Must be installed in safe-area control cabinet only. Blue terminals = intrinsically safe side (connect to field explosion-proof sensors). White/red terminals = non-intrinsically safe side (connect to PLC and power supply).

제품명: Isolated Intrinsically Safe Switch Amplifier

메모: WE77/Ex-2 is an obsolete legacy model. Recommended replacement for new projects: KFA6-SR2-Ex2

1. 모델 코드 정의

WE77: 제품군, NAMUR switch amplifier

전: Intrinsically safe explosion-proof design

2: Dual-channel version (WE77/Ex-1 = single-channel)

Two power supply variants:

1. WE77/Ex-2 115V: 115V AC 공급
2. WE77/Ex-2 230V: 230다섯 (220다섯) AC supply, most common in China
3. 핵심 기능

Intrinsically safe isolated barrier for NAMUR sensors and dry contact mechanical switches located in hazardous areas. It isolates and transmits binary switch signals from hazardous area to control system in safe area. Equipped with LB Lead Breakage detection, supports reverse operation mode. Each channel has independent relay change-over contact output.

필드사이드: Intrinsically safe circuit EEx ia IIC, suitable for Zone0/1/2 hazardous locations

Control side: Passive relay dry contact output (non-intrinsically safe)

Supported inputs: NAMUR proximity sensors (EN60947-5-6), passive mechanical contacts

3. 주요 전기 사양

Intrinsically Safe Parameters (Field Side)

U₀: 13.5 DC에서

I₀: 62 엄마

P₀: 125 밀리와트

Explosion group: IIB / IIC

Permitted external values: IIB: Co=0.929µF, Lo=5mH; IIC: Co=0.23µF, Lo=3mH

NAMUR Input

Open circuit voltage ≈8V DC, short-circuit current ≈8mA

Switching threshold: 1.2~2.1mA, hysteresis approx.0.2엄마

Lead breakage detection: Fault alarm upon cable disconnection

릴레이 출력 (1 SPDT change-over contact per channel)

접점등급: 250V AC /4A; 24VDC/4A

응답 시간: Pull-in ≈10ms, Drop-out ≈20ms

Max switching frequency: ＜10Hz

기계적 수명: 10⁷ switching cycles

전원공급장치

230V version: 198~253V AC, 45~65Hz; Power dissipation approx.2.5W

115V version: 103.5~126V AC, 45~65Hz

4. 기계 & 환경 데이터

차원: 40(여) ×104(시간) ×110(디) mm

무게: approx.410g

설치: DIN rail clip mounting

Enclosure protection: IP20 (for cabinet installation only)

주변 온도: -25℃ ~ +60℃

터미널: 나사 터미널

5. 인증정보

ATEX 인증서: PTB 02 ATEX 2065 / PTB Ex-79/2043X

Explosion marking: II (1) GD [EEx ia] IIC

6. 터미널 할당 (WE77/Ex-2)

Channel1 field input: 단말기 1(-), 2(+)

Channel2 field input: 단말기 8(+), 9(-)

Channel1 relay output: 10/11/12 (change-over contact)

Channel2 relay output: 13/14/15 (change-over contact)

전원공급장치: 17, 18

7. 애플리케이션

화학적인, 제약, 기름 & 가스 위험 장소: Signal isolation for NAMUR proximity sensors, explosion-proof limit switches, explosion-proof level switches. Relay signals are sent to PLC/DCS DI modules.

8. 예비 부품 & 교체 노트
9. WE77/Ex-2 no longer recommended for new projects by manufacturer. 직접 교체: KFA6-SR2-Ex2 (dual-channel NAMUR safety barrier, 릴레이 출력, equivalent function, smaller footprint)
10. For maintenance of existing systems: Only surplus / stock spare parts available. Confirm 115V or 230V variant before procurement, the two versions are not interchangeable.
11. Single-channel equivalent: WE77/Ex-1, replacement KFA6-SR1-Ex
12. 일반적인 문제 해결
13. No input response: Check for LB lead breakage alarm on NAMUR loop; verify external capacitance/inductance does not exceed intrinsic safety limits
14. Relay fails to switch: Confirm power supply variant matches device rating; verify input current falls within NAMUR operating range
15. Frequent false lead breakage alarm: Excessive cable length with high distributed capacitance/inductance, or damaged cable insulation
16. 기계적인 설치
17. DIN 레일: 표준 35mm DIN 레일 장착. Hook top clip onto rail, press module down to lock. 제거하려면: Lift bottom latch and pull outward.
18. 운영 환경

주변 온도: -25℃ ~ +60℃, cabinet ventilation required; 열원에서 멀리 유지, vibration and corrosive gas

보호 등급 IP20, 실내 캐비닛 전용, not for open or humid direct exposure

Mounting clearance: Small gaps between adjacent modules recommended for heat dissipation

3. Mandatory Explosion Protection Rules

✅ Unit must be mounted in safe area, NEVER install in Zone0/1/2 hazardous areas

✅ Intrinsically safe cables (파란색) and non-intrinsically safe cables (힘, 릴레이 출력) must run in separate trunking/conduits, cannot share same conduit

2. Terminal Table

중요한: NAMUR field wiring is polarity sensitive. Reversed polarity will trigger LB lead breakage fault and unit malfunction.

3. Wiring Schemes

계획 1: NAMUR Proximity Sensor (가장 일반적인)

Channel1: 2-wire NAMUR sensor → Terminals 1(-), 2(+)

Channel2: 2-wire NAMUR sensor → Terminals 8(+), 9(-)

NAMUR loop includes LB lead breakage monitoring: Cable break, short circuit or reversed polarity will trigger channel fault LED.

계획 2: Explosion-proof Passive Dry Contact (리미트 스위치)

Dry contact directly connected to IS terminals, lead breakage detection remains active. No external supply for contact; WE77/Ex-2 provides approx.8V/8mA IS drive internally.

Relay Output Wiring (to PLC DI)

Each channel is SPDT passive change-over contact, no external supply required

Channel1: 11 흔한, 12 아니요, 10 NC

Channel2: 14 흔한, 15 아니요, 13 NC

Contact maximum rating: 250뷔와 / 4에이; 24VDC /4A. Do not overload to avoid contact burnout.

Power Wiring

터미널 17 & 18 for AC supply:

WE77/Ex-2 230V version: AC 198~253V (Mainland China standard)

WE77/Ex-2 115V version: AC 103.5~126V

⚠️ Hardware differs between two power versions, NOT interchangeable.

4. 케이블 선택 (Explosion Compliance Mandatory)
5. Intrinsically safe side (Blue terminals to field instrument): Blue IS cable recommended, conductor cross-section ≥0.5mm², rated voltage ≥500V
6. Intrinsically safe loop must be verified for maximum permitted cable capacitance Co and inductance Lo:

IIC application: Co ≤0.23µF, Lo ≤3mH

IIB application: Co ≤0.929µF, Lo ≤5mH

Excessive cable length causes distributed capacitance/inductance over-limit, invalidating intrinsic safety certification.

3. Shielded cable: Shield single-point earthed at control room end, shield floating at hazardous area side to prevent earth loop current.
4. 배선 절차 (Safety Sequence)
5. 전원 끄기! Isolate all power sources and confirm zero voltage before wiring
6. Connect field intrinsically safe cables first (blue terminals), verify polarity
7. Connect relay output cables to PLC DI modules
8. Connect module power terminals 17 &18 마지막
9. Tighten all screw terminals, no loose strands or exposed copper causing short circuit
10. 사전 전원 확인: IS cables separated from power cables, no mixed routing
11. Power-on commissioning: Power on without field load first and check channel LEDs. Connect field sensors, test switching action and LB fault function.
12. 시운전 & LED 표시

Independent LED per channel: Illuminated when valid input signal present; LB lead breakage fault will extinguish LED / trigger fault alarm

작동 모드: Reversible mode available (relay de-energizes when input activates), configurable per project requirement

Lead breakage test: Disconnect field sensor wire, module shall detect line fault and activate LB alarm.

7. Critical Prohibitions & 일반적인 함정
8. ❌ Megger insulation test is forbidden on intrinsically safe terminals! High voltage from megger will destroy internal IS circuit and permanently damage unit. Remove all IS wiring before any cable high voltage test.
9. ❌ Never route 220V power cables or non-IS signal wires into blue intrinsically safe terminals; intrinsic safety protection will be destroyed.
10. ❌ IS circuits and non-IS circuits cannot share same cable or trunking.
11. ❌ Do not install WE77/Ex-2 in hazardous area.
12. ❌ Do not exceed Co/Lo intrinsic safety limits, explosion certification will be invalid.
13. ❌ Do not overload relay contacts; damaged relay contacts cannot be repaired separately, full module replacement required.
14. Earthing Instruction

WE77/Ex-2 is transformer-isolated safety barrier; galvanic isolation between IS side and control side. Module housing connected to cabinet protective earth as standard, earth resistance ≤4Ω. Isolated barrier does NOT require dedicated intrinsic safety earth like zener barriers.

9. Post Power-On Quick Fault Diagnosis
10. No LED illumination after power-up: Check voltage at terminal 17/18, confirm 115V/230V model match, check loose power terminals.
11. Persistent LB fault alarm: ①NAMUR polarity reversed; ②broken cable; ③cable distributed capacitance/inductance over-limit; ④field sensor damaged.
12. Sensor switches but relay does not toggle: Verify NAMUR current within operating range; check NO/NC contact selection.
13. Unintended relay chattering/false switching: 전력 변동, 전자기 간섭. Use shielded cable and separate strong/weak signal wiring.

WE77/Ex-2 Intrinsically Safe Blue Terminals & Non-Intrinsically Safe Relay Terminal Current Parameters

Distinguish between intrinsic safety certified maximum short-circuit current Io (explosion parameter) and NAMUR normal operating current. Non-intrinsically safe side is relay contact rated current.

🔵 Blue Terminals: Intrinsically Safe Field Input Side

WE77/Ex-2 230V version (Mainland China mainstream)

1. Intrinsic safety maximum short-circuit current Io = 62mA (certified explosion parameter. In short-circuit condition, module limits output current below this value to maintain explosion safety)
2. NAMUR normal operating current: Open circuit ≈8V DC, static short-circuit current ≈8mA; Switching threshold 1.2~2.1mA per NAMUR standard

Note for 115V WE77/Ex-2 variant: Io=31mA. Always confirm power supply version during selection.

⚠️ 중요: 62mA is the safety limit short-circuit current, NOT normal working current. Under normal NAMUR sensor operation, loop current is only a few milliamps.

⚪ White Terminals: Non-intrinsically Safe Relay Output (터미널 10/11/12,13/14/15)

SPDT change-over contact rated load current (저항 부하) per channel

AC 250V: 4에이 (cosφ>0.7)

DC 24V: 4에이

DC 60V: 0.6에이

DC 220V: 0.1에이

Max contact power rating: 500버지니아; Overload will cause contact erosion, module non-repairable.

추가의: Module Power Terminals (17,18)

Total power dissipation approx.2.5W. For 230V AC supply, power loop current is low, 대략.0.01에이.

Summary Table