The Allen-Bradley 1794-TB32, also cataloged as the 1794-TB32 FLEX I/O Terminal Base Unit, operates as a dedicated hardware component for field signal termination and backplane bus routing within FLEX I/O control systems.
Hardware Specifications
Parameter
Specification
Model
1794-TB32
Brand
Allen-Bradley
Origin
USA
Weight
0.75 lbs (0.34 kg)
Dimensions
Standard FLEX I/O base footprint
Operating Temp
-20 to 70 deg C
Input Voltage Range
19.2 to 31.2 VDC (24 VDC nominal)
Current Rating
10 A max
Flexbus Output Current
640 mA
Isolation Voltage
50 V continuous
Termination Type
Cage Clamp
I/O Capacity
32 I/O Terminals
Power Terminals
8 Common Terminals, 8 +V Terminals
Communication Rate
57.6 kbps to 230 kbps
Mounting Format
DIN-rail / Panel Mount
I/O Density Scaling and Backplane Bus Velocity
The 1794-TB32 terminal base enables high I/O density scaling by providing 32 I/O field termination points alongside integrated 8 common and 8 +V power connections within a single compact footprint. Designed to supply up to 640 mA of Flexbus output current across 24 VDC nominal voltage paths, the internal architecture maintains deterministic backplane bus communication velocity across data rates from 57.6 kbps up to 230 kbps. Signal pathways feature 50 V continuous isolation to shield sensitive backplane logic circuits from transient field noise during high-speed parallel digital I/O execution.
Frequently Asked Questions
Q: Can high-density 32-point modules mounted on the 1794-TB32 be hot-swapped during active system operation?
A: Yes. The 1794-TB32 houses the continuous internal backplane pass-through routing, permitting Removal and Insertion Under Power (RIUP) of the active 32-point I/O module without breaking communication continuity across adjacent FLEX I/O node units.
Q: How are power expansion connections configured on the 1794-TB32 terminal base?
A: The base unit contains 8 factory-bussed +V terminals and 8 common terminals, allowing direct 2-wire or 3-wire field device power distribution without requiring external terminal strips.
Field Installation Guidelines
Latch the terminal base unit securely onto an earth-grounded 35 mm DIN rail until the rear mounting spring engages completely.
Push the base unit laterally against the adjacent FLEX I/O adapter or base module to fully engage the female-to-male Flexbus connectors.
Wire field conductors to the 32 cage-clamp I/O terminals and dedicated power rails, ensuring wire insulation is stripped to 9 mm (0.35 in).
Connect the main 24 VDC field power supply across the primary power terminals, maintaining proper polarity within the 19.2 to 31.2 VDC operating range.
Verify that the DIN-rail grounding foot makes clean, paint-free metallic contact with the enclosure rail surface to preserve internal isolation ratings.
