Pepperl+Fuchs WE77/Ex-2 Isolated Switch Amplifier

ペッパール+フックス WE77/Ex-2 Installation & 配線ガイド

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).

製品名: Isolated Intrinsically Safe Switch Amplifier

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

1. モデルコードの定義

WE77: Product family, NAMUR switch amplifier

元: 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 supply
2. WE77/Ex-2 230V: 230V (220V) AC supply, most common in China
3. コア機能

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.

Field side: 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. 主要な電気仕様

Intrinsically Safe Parameters (フィールドサイド)

U₀: 13.5 ワシントンDCで

I₀: 62 ミリアンペア

P₀: 125 mW

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.0.2ミリアンペア

Lead breakage detection: Fault alarm upon cable disconnection

リレー出力 (1 SPDT change-over contact per channel)

接点定格: 250V AC /4A; 24VDC/4A

応答時間: Pull-in ≈10ms, Drop-out ≈20ms

最大スイッチング周波数: ＜10Hz

機械的寿命: 10⁷ switching cycles

電源

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

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

4. 機械式 & 環境データ

寸法: 40(W) ×104(H) ×110(D) mm

重さ: approx.410g

取り付け: DIN rail clip mounting

Enclosure protection: IP20 (キャビネット設置のみ)

周囲温度: -25℃～+60℃

端子: ネジ端子

5. 認証情報

ATEX証明書: PTB 02 アテックス 2065 / PTB Ex-79/2043X

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

6. Terminal Assignment (WE77/Ex-2)

Channel1 field input: ターミナル 1(-), 2(+)

Channel2 field input: ターミナル 8(+), 9(-)

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

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

電源: 17, 18

7. 応用

化学薬品, 製薬, 油 & gas hazardous locations: Signal isolation for NAMUR proximity sensors, explosion-proof limit switches, explosion-proof level switches. Relay signals are sent to PLC/DCS DI modules.

8. スペアパーツ & 交換ノート
9. WE77/Ex-2 no longer recommended for new projects by manufacturer. 直接交換: KFA6-SR2-Ex2 (dual-channel NAMUR safety barrier, リレー出力, 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. よくあるトラブルシューティング
13. 入力応答なし: 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. 機械的設置
17. DINレール: 標準 35mm DIN レール取り付け. Hook top clip onto rail, press module down to lock. 削除するには: Lift bottom latch and pull outward.
18. 動作環境

周囲温度: -25℃～+60℃, cabinet ventilation required; keep away from heat sources, vibration and corrosive gas

保護等級IP20, indoor cabinet use only, 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 (青) and non-intrinsically safe cables (力, リレー出力) must run in separate trunking/conduits, cannot share same conduit

2. Terminal Table

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

3. Wiring Schemes

スキーム 1: NAMUR Proximity Sensor (最も一般的な)

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.

スキーム 2: Explosion-proof Passive Dry Contact (リミットスイッチ)

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 一般, 12 いいえ, 10 ノースカロライナ州

Channel2: 14 一般, 15 いいえ, 13 ノースカロライナ州

Contact maximum rating: 250Vと / 4あ; 24VDC /4A. Do not overload to avoid contact burnout.

電源配線

端子 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. ケーブルの選択 (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. 配線手順 (Safety Sequence)
5. 電源を切る! 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 last
9. すべてのネジ端子を締めます, no loose strands or exposed copper causing short circuit
10. 電源前のチェック: 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. 試運転 & LED表示

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

動作モード: 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 & Common Pitfalls
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: 電力変動, 電磁干渉. 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.

⚠️重要: 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 (端子 10/11/12,13/14/15)

SPDT change-over contact rated load current (抵抗負荷) per channel

AC 250V: 4あ (cosφ>0.7)

DC24V: 4あ

DC 60V: 0.6あ

DC220V: 0.1あ

Max contact power rating: 500バージニア州; Overload will cause contact erosion, module non-repairable.

Additional: Module Power Terminals (17,18)

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

Summary Table