ICS T8850,Trusted 40‑Channel High‑Current Digital Output Field Termination Assembly(FTA)

1. Basic Information

2. Electrical Specifications

• Channel quantity：40 digital output channels, 2‑wire field wiring
• Field nominal voltage：24 VDC; operating range 18‑32 VDC
• Channel grouping：40 channels divided into 5 independent power groups, 8 channels per group
• Field power input：Dual redundant 24 VDC field power supply with diode OR‑ing for each group
• On‑board indicator：One green status LED per power group for field power monitoring
• Protection：Group‑level replaceable fuse for each power group
• FTA characteristic：Passive termination assembly, no active onboard power consumption
• Insulation：500 VDC isolation, insulation resistance＞100 MΩ
• Terminal wire gauge：12 AWG‑24 AWG
• Hot‑swap support：Replace T8451 module without disconnection of field cables

3. Environmental Conditions

• Operating temperature：0 ℃ ~ +60 ℃
• Storage temperature：‑20 ℃ ~ +70 ℃
• Relative humidity：5‑95 % RH, non‑condensing
• Enclosure rating：IP20 (cabinet‑mount installation only)
• Approvals：IEC 61508 SIL‑3 system compatible, ATEX, IECEx, UL, CE certified
• Conformal coating：Not available. Off‑shore projects select conformal‑coated I/O module T8451C, FTA keeps standard T8850.

4. Main Functions

1. 40‑channel field termination for high‑current DO loops: Interface between T8451 high‑current output module and field solenoid valves, shutdown actuators.
2. Five electrically independent power groups (8 channels each), group‑wise fuse protection; fault in one group will not affect other groups.
3. Dual redundant 24 VDC field power input with diode OR‑ing circuit for improved power availability.
4. Per‑group power‑status LED for fast field‑power troubleshooting.
5. SmartSlot hot‑swap architecture: T8451 I/O module can be replaced online without removing field wiring.
6. Fully compatible with TMR 2‑out‑of‑3 safety architecture for ESD emergency‑shutdown safety loops.

5. Typical Applications

1. On‑shore & offshore platform SIS‑ESD emergency‑shutdown system for high‑current 24 VDC solenoid‑valve driving.
2. Safety‑critical shutdown actuator output loops within Fire&Gas system.
3. Strictly matched only with T8451 / T8451C high‑current DO module, incompatible with other DO modules (T8448, T8461).

Trusted T88xx FTA cross‑reference

|FTA Part‑No.|Description|Matched I/O Module|

|—|—|—|

|T8800|40‑Ch DI FTA|T8403 / T8403C|

|T8842|40‑Ch Configurable DI/DO FTA|T8448 / T8448C|

|T8850|40‑Ch High‑Current DO FTA|T8451 / T8451C|

|T8861|40‑Ch 24/48VDC DO FTA|T8461 / T8461C|

6. Important Notes

1. No conformal‑coated “C” version for T8850. Off‑shore projects: use T8451C(conformal coated I/O card) + standard T8850 FTA.
2. Only pair with T8451 / T8451C high‑current digital‑output module, cannot be used with T8448 or T8461.
3. Each power‑group has replaceable group fuse; blown fuse must be replaced with specified rating.
4. Install inside certified control cabinet on DIN‑rail; cannot mount directly in hazardous zone.
5. External 24 VDC field power must be supplied for output actuator loops.