1756-OA16I — 1756 16-Point Individually Isolated AC Output Module

The 1756-OA16I is a 16-point AC output module for the 1756 chassis with every output individually isolated from the backplane and from every other point on the module. Each channel switches up to 2A at 30°C ambient (1A at 60°C) within a 74–265V AC operating range, with the module total capped at 5A at 30°C (4A at 60°C). Configurable point-level fault states let each output independently hold last state, go off, or go on if communication with the controller is lost.

Specifications

Parameter	Value
Part Number	1756-OA16I
Platform	1756 Logix chassis
Output Points	16, individually isolated
Voltage Range	74–265V AC, 47–63 Hz
Current per Point	2 A @ 30°C, 1 A @ 60°C (linear derating)
Current per Module	5 A @ 30°C, 4 A @ 60°C
Output Delay (ON/OFF)	9.3 ms @ 60 Hz, 11 ms @ 50 Hz
Isolation Voltage	250V continuous, output-to-backplane and output-to-output
Internal Fusing	None — external fusing required
RTB Options	1756-TBCH or 1756-TBS6H
Operating Temperature	0°C to 60°C

Why Individual Isolation Matters at This Density

At 16 points per module, a group-common output design saves wiring complexity but means every channel shares a return reference — appropriate when all connected loads share the same supply, but a liability when they don't. The 1756-OA16I isolates every point individually, both from the backplane and from each other, so any combination of AC voltages within the rated range, supplied from different sources, can be wired across the 16 outputs without ground loop interaction between channels.

The absence of internal fusing is a deliberate design choice rather than an oversight — it gives the system designer full control over branch circuit protection sized to each specific load, rather than a fixed internal fuse rating that might not match every connected device. External fusing per output circuit, sized appropriately to the connected load, is the standard practice for this module given that design.

FAQ

Q: Does the lack of internal fusing mean this module is less protected than a fused alternative?

No — it shifts protection responsibility to externally-installed, load-specific fusing rather than a generic internal fuse. This gives more precise protection matched to each connected device's actual current rating.

Q: Can different output points run at different AC voltages simultaneously?

Yes. Because every point is individually isolated, any mix of voltages within the 74–265V AC range can be wired across the 16 outputs, including from separate, unrelated supply sources.

Q: What happens to outputs if communication with the controller is lost?

Each point's fault behavior is independently configurable — hold last state, go off, or go on — set per channel in the controller's I/O configuration to match each connected device's required fail-safe behavior.

Q: What removable terminal blocks are compatible with this module?

The 1756-TBCH (cage-clamp) and 1756-TBS6H (screw-clamp) RTBs both work — both are ordered separately from the module itself, and the choice depends on the panel's preferred wiring termination style.

1756-OA16I New Sealed 1756OA16 /A 16 Point D/O Module