Allen-Bradley 1797-TB3S Terminal Base Unit
The Allen-Bradley 1797-TB3S, also cataloged as the 1797-TB3S Terminal Base Unit, operates as a dedicated hardware component for intrinsically safe field wiring termination within FLEX Ex I/O networks. This DIN-rail mounted base provides 52 spring-clamp termination points arranged in three distinct rows to facilitate direct electrical interconnections between hazardous area field devices and installed FLEX Ex intrinsically safe I/O modules.
Suffix Breakdown & Model Matrix
| Part Number | Terminal Type | Total Terminals | Row Layout Configuration | System Architecture |
|---|---|---|---|---|
| 1797-TB3S | Spring Clamp | 52 | 2 Rows x 18 Terminals, 1 Row x 16 Terminals | FLEX Ex Hazardous Area (Ex i) |
| 1797-TB3 | Screw Clamp | 52 | 2 Rows x 18 Terminals, 1 Row x 16 Terminals | FLEX Ex Hazardous Area (Ex i) |
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | 1797-TB3S |
| Brand | Allen-Bradley |
| Origin | USA |
| Weight | 0.37 kg (0.81 lbs) |
| Dimensions | Standard FLEX Ex Terminal Base Form Factor |
| Operating Temp | -20 deg C to +70 deg C (-4 deg F to +158 deg F) |
| Storage Temp | -40 deg C to +85 deg C (-40 deg F to +185 deg F) |
| Power Consumption | Passive Backplane Bus Interface |
| Terminal Count | 52 Spring-Clamp Terminals |
| Terminal Layout | 2 Rows of 18 Terminals, 1 Row of 16 Terminals |
| Isolation Voltage | Channel-to-channel isolation determined by installed module |
| Relative Humidity | 5% to 95% (non-condensing) |
| Shock Resistance | Tested up to 15 g operational shock |
Deterministic Backplane Bus Communications and Intrinsic Safety Execution
The 1797-TB3S base unit establishes direct backplane bus communication velocity and power routing for intrinsically safe (Ex i) FLEX Ex I/O modules. Operating within deterministic EtherNet/IP or ControlNet topologies, the internal copper bus traces deliver high-density I/O signal routing without introducing electrical impedance that could jeopardize intrinsically safe entity parameters. The mechanical keying mechanism ensures firmware flash compatibility and prevents incorrect module insertion into hazardous location backplanes.
Frequently Asked Questions
Q: Does the 1797-TB3S support live module insertion and removal (RIUP/hot-swapping) in hazardous environments?
A: Yes, the 1797-TB3S terminal base permits hot-swapping of FLEX Ex modules under power, provided the installed module maintains intrinsic safety ratings and the backplane connector shield remains grounded.
Q: What wire gauge range is supported by the spring-clamp terminals on the 1797-TB3S?
A: The spring-clamp mechanism accommodates solid or stranded copper conductors ranging from 0.5 mm2 to 2.5 mm2 (22 AWG to 12 AWG) rated for hazardous location wiring requirements.
Field Installation Guidelines
- Snap the 1797-TB3S securely onto a standard 35 mm DIN rail (EN 50022), verifying that the grounding spring establishes a solid electrical link to the grounded metal rail.
- Align the mechanical keyswitch on the terminal base to match the specific keying position required by the selected FLEX Ex I/O module before installing the active hardware.
- Strip field conductor insulation to 10 mm (0.4 in), insert a flathead screwdriver into the spring release slot, insert the wire fully into the terminal clamp, and release to lock.
- Maintain strict physical separation (minimum 50 mm clearance) between intrinsically safe (Ex i) field wiring connected to the 1797-TB3S and non-intrinsically safe wiring conductors within the enclosure.
Allen-Bradley 1797-TB3S Terminal Base Unit
Allen-Bradley 1797-TB3S Terminal Base Unit
The Allen-Bradley 1797-TB3S, also cataloged as the 1797-TB3S Terminal Base Unit, operates as a dedicated hardware component for intrinsically safe field wiring termination within FLEX Ex I/O networks. This DIN-rail mounted base provides 52 spring-clamp termination points arranged in three distinct rows to facilitate direct electrical interconnections between hazardous area field devices and installed FLEX Ex intrinsically safe I/O modules.
Suffix Breakdown & Model Matrix
| Part Number | Terminal Type | Total Terminals | Row Layout Configuration | System Architecture |
|---|---|---|---|---|
| 1797-TB3S | Spring Clamp | 52 | 2 Rows x 18 Terminals, 1 Row x 16 Terminals | FLEX Ex Hazardous Area (Ex i) |
| 1797-TB3 | Screw Clamp | 52 | 2 Rows x 18 Terminals, 1 Row x 16 Terminals | FLEX Ex Hazardous Area (Ex i) |
Hardware Specifications
| Parameter | Specification |
|---|---|
| Model | 1797-TB3S |
| Brand | Allen-Bradley |
| Origin | USA |
| Weight | 0.37 kg (0.81 lbs) |
| Dimensions | Standard FLEX Ex Terminal Base Form Factor |
| Operating Temp | -20 deg C to +70 deg C (-4 deg F to +158 deg F) |
| Storage Temp | -40 deg C to +85 deg C (-40 deg F to +185 deg F) |
| Power Consumption | Passive Backplane Bus Interface |
| Terminal Count | 52 Spring-Clamp Terminals |
| Terminal Layout | 2 Rows of 18 Terminals, 1 Row of 16 Terminals |
| Isolation Voltage | Channel-to-channel isolation determined by installed module |
| Relative Humidity | 5% to 95% (non-condensing) |
| Shock Resistance | Tested up to 15 g operational shock |
Deterministic Backplane Bus Communications and Intrinsic Safety Execution
The 1797-TB3S base unit establishes direct backplane bus communication velocity and power routing for intrinsically safe (Ex i) FLEX Ex I/O modules. Operating within deterministic EtherNet/IP or ControlNet topologies, the internal copper bus traces deliver high-density I/O signal routing without introducing electrical impedance that could jeopardize intrinsically safe entity parameters. The mechanical keying mechanism ensures firmware flash compatibility and prevents incorrect module insertion into hazardous location backplanes.
Frequently Asked Questions
Q: Does the 1797-TB3S support live module insertion and removal (RIUP/hot-swapping) in hazardous environments?
A: Yes, the 1797-TB3S terminal base permits hot-swapping of FLEX Ex modules under power, provided the installed module maintains intrinsic safety ratings and the backplane connector shield remains grounded.
Q: What wire gauge range is supported by the spring-clamp terminals on the 1797-TB3S?
A: The spring-clamp mechanism accommodates solid or stranded copper conductors ranging from 0.5 mm2 to 2.5 mm2 (22 AWG to 12 AWG) rated for hazardous location wiring requirements.
Field Installation Guidelines
- Snap the 1797-TB3S securely onto a standard 35 mm DIN rail (EN 50022), verifying that the grounding spring establishes a solid electrical link to the grounded metal rail.
- Align the mechanical keyswitch on the terminal base to match the specific keying position required by the selected FLEX Ex I/O module before installing the active hardware.
- Strip field conductor insulation to 10 mm (0.4 in), insert a flathead screwdriver into the spring release slot, insert the wire fully into the terminal clamp, and release to lock.
- Maintain strict physical separation (minimum 50 mm clearance) between intrinsically safe (Ex i) field wiring connected to the 1797-TB3S and non-intrinsically safe wiring conductors within the enclosure.
