1794-TB32S — FLEX I/O 32-Point Spring Clamp Terminal Base

The 1794-TB32S is a 32-point spring clamp terminal base for the 1794 FLEX I/O system. It's the physical mounting base that a FLEX I/O module body clips into — it stays in the panel, holds the field wiring, and provides the backplane power rail connection. The module itself can be removed and replaced without disturbing the wired terminals. The spring clamp termination style accepts wire without a screwdriver and releases with a small flathead or push-in tool, which speeds up field wiring on high-density installations.

Thirty-two terminals accommodate the full wiring complement of FLEX I/O modules with up to 32 I/O points. This matches high-density output modules like the 1794-OB32P or the 1794-OV32, as well as analog modules with multiple channels and their associated signal and supply terminals. Choosing the correct terminal base for each module — the right point count, termination style, and power rail configuration — is a step that determines the physical wiring layout for the entire node.

Specifications

Parameter	Value
Part Number	1794-TB32S
Platform	FLEX I/O (1794)
Terminal Count	32
Termination Style	Spring clamp (tool-free insert, push-to-release)
Wire Range	0.14–1.5 mm² (26–16 AWG)
Max Wire Gauge (solid)	1.5 mm² (16 AWG)
Power Rail	Passes V+ and V− to next base in node
Field Power Pass-Through	Yes
Mounting	35 mm DIN rail
Compatible Modules	1794-series 32-point I/O modules
Operating Temperature	−20°C to 55°C
Standards	UL 508, CE, IEC 61131-2

The Terminal Base Role in a FLEX I/O Node

In a FLEX I/O node, the adapter module (handling network communication) connects to a chain of terminal bases on the DIN rail. Each terminal base carries two things: the backplane data bus that connects the adapter to each I/O module, and the field power rail that supplies the I/O module's field circuits. The module body clips into the terminal base and connects to both.

When a module needs to be replaced, the terminal base stays in place with all its wiring intact. The module body unclips, the replacement clips in, and the I/O is restored without touching a single wire. This is the core maintenance advantage of the FLEX I/O architecture — field replacement is a tool-free, wiring-free operation that takes minutes.

The 1794-TB32S passes the field power rails (V+ and V−) from its left connector to its right connector, continuing the power chain along the node. If a new power segment is needed at this base's position, a power extender module (such as the 1794-TB3S with extender connections) is used instead. The TB32S simply passes whatever field power it receives from the left side to the right side.

FAQ

Q: Can any 1794 I/O module be used with this terminal base?

No — the terminal base must match the module's terminal count. The 1794-TB32S is for 32-point modules. Using it with an 8-point or 16-point module leaves terminals unconnected and wastes wiring positions. Check the I/O module's documentation for the compatible terminal base catalog numbers.

Q: What wire gauge is recommended for field wiring?

The spring clamp accepts 0.14–1.5 mm² (26–16 AWG). For 24V DC digital I/O, 0.5–0.75 mm² (20 AWG) is typical. For analog signals, use 0.5 mm² shielded twisted pair. Avoid over-sizing wire — 1.5 mm² (16 AWG) wire is at the upper limit and can be stiff enough to stress the terminal clamp over time.

Q: Is the module hot-swap capable when using this terminal base?

Hot-swap depends on the adapter module type, not the terminal base. Some FLEX I/O adapters support module removal under power; others require the bus to be de-energized. Verify the adapter's hot-swap capability in its user manual before attempting live module replacement.

Q: Does field power need to be connected at every terminal base?

Field power enters the node at the adapter or the first terminal base with a field power connection, and passes through subsequent bases via the power rail. The 1794-TB32S passes power through automatically — you only need to connect field power at the entry point of each power segment, not at every base individually.

1794-TB32S New Factory Sealed 1794TB32S SER A Flex I/O 24VDC Output Module