Allen-Bradley 1746-OG16 TTL Output Module SLC 500

1746-OG16 16-Channel 5V DC Sink Output Module

Product Introduction

The 1746-OG16 from Allen-Bradley provides sixteen TTL-compatible sinking outputs in a single-slot SLC 500 package. This output module operates within a 4.5-5.5V DC range, making it specifically suited for 5V TTL logic circuits. Each channel delivers 24mA continuous current, with a total module current of 384mA. A distinctive feature is its inverted logic, which requires a NOT instruction in your program for proper operation. This output module occupies one slot in SLC 500 fixed or modular chassis and needs an external 5V DC power supply to energize output circuitry.

Key Technical Specifications

The 1746-OG16 features sixteen output points sharing a single common +VDC terminal. Each output provides 24mA continuous current, with a maximum module current of 384mA. Backplane current consumption is 180mA at 5V DC, while the 24V DC backplane draws 0mA. Off-state leakage current stays below 0.1mA, ensuring reliable TTL signal integrity. The off-state voltage ranges from 4.5-5.5V DC, matching typical TTL high-level specifications.

Signal delay characteristics include 0.25mA for turn-on and 0.50mA for turn-off. The step response measures 60ms for turn-on and 2.5ms for turn-off. Maximum ripple allowed on the external supply is 50mV peak-to-peak, which is essential for stable TTL operation. Additionally, this output module has a maximum on-state voltage drop that maintains proper TTL low-level thresholds.

Inverted Logic and Programming Considerations

A critical aspect of the 1746-OG16 is its inverted logic architecture. When you energize an output bit in your program, the corresponding physical output turns off. Conversely, when you de-energize the bit, the output turns on. Therefore, you must insert a NOT instruction in your ladder logic for each output channel to achieve normal, non-inverted operation.

For example, if you want to turn on an output when a sensor activates, you would program: Sensor Contact → NOT → Output Coil. This arrangement negates the natural inversion, producing the expected behavior. The data table allows you to monitor individual channels or force them on/off for testing purposes. You can view the data table in binary, decimal, octal, or hexadecimal formats. During programming, the data table supports drag-and-drop operations for efficient configuration.

TTL Load Compatibility

This output module excels at driving TTL-compatible loads, such as LED displays, solid-state relays with TTL inputs, and logic-level interface circuits. Its sinking configuration means the output switches the load to ground (0V) when active, which is standard for many TTL devices. The 1746-OG16 is also suitable for sink-load displays that require a common positive supply. Always verify that your external load operates within the 4.5-5.5V DC range and does not exceed 24mA per channel.

Environmental and Mechanical Ratings

Operating temperature for the 1746-OG16 ranges from -13°F to 140°F (-25°C to 60°C), while non-operating temperature spans -40°F to 185°F (-40°C to 85°C). Humidity tolerance is 5-95% relative humidity without condensation. Vibration resistance includes 2g at 10-500 Hz and 2.5g at 57-2000 Hz, with an operating shock rating of 30g. This output module is intended for industrial environments with pollution level no higher than Pollution 2 as defined in EN/IEC 60664-1.

Installation and Configuration

Installing the 1746-OG16 is straightforward. Slide the module into any available slot within an SLC 500 fixed or modular chassis. The backplane supplies 5V DC power for internal logic, but you must connect an external 4.5-5.5V DC power supply to energize the output circuitry. The sixteen outputs share a single common +VDC terminal, simplifying wiring for groups of TTL loads.

Field wiring connects via the front-facing terminal block. Recommended signal wire size is up to 2 mm² (14 AWG). Configuration occurs through your programming software, where you set up the data table and apply NOT instructions as needed. For optimal performance, ensure the external supply voltage remains stable within the specified range, with ripple under 50mV peak-to-peak.

Safety and Disconnection Guidelines

This output module is designed for industrial environments and should be mounted inside an enclosure accessible only by qualified personnel. Do not disconnect equipment unless power has been removed and the area is known to be non-hazardous, as electrical arcs may occur during disconnection. Always follow proper lockout/tagout procedures when servicing the module or connected loads.

Typical Applications

The 1746-OG16 is primarily used in applications requiring TTL-level control signals. For instance, it drives LED matrix displays, indicator panels, and solid-state relay banks in automated test equipment. It also interfaces with PLC-to-PLC communication links using TTL logic levels. In addition, this output module suits applications where sinking outputs are preferred, such as driving common-anode LED displays. Common industries include electronics manufacturing, semiconductor testing, and laboratory automation.

Packaging List

• 1 x Allen-Bradley 1746-OG16 TTL output module

• 1 x Removable terminal block (installed)

• 1 x Slot filler label

• 1 x Quick-start guide (printed)

Note: External 5V DC power supply, cables, and programming software are sold separately.

Shipping Information

All orders ship via FedEx, UPS, or DHL with full tracking and insurance coverage. Expedited shipping options are available upon request. Domestic deliveries typically arrive within 2–3 business days, while international shipments take 5–7 days depending on customs clearance.

Frequently Asked Questions (FAQ)

Q1: Why does my output turn on when the program bit is off?
This occurs because the 1746-OG16 has inverted logic. You must add a NOT instruction in your ladder logic before the output coil to correct this behavior.

Q2: Can I use the 1746-OG16 to drive standard 24V DC loads?
No. This output module operates only at 4.5-5.5V DC and cannot handle 24V loads. Using it with higher voltages will damage the module. Consider the 1746-OB8 or 1746-OBP8 for 24V applications.

Q3: What is the maximum current per output on the 1746-OG16?
Each output supports 24mA continuous current. Exceeding this limit may damage the output transistor. For higher current requirements, use an interposing transistor or relay.

Q4: Does the 1746-OG16 require an external power supply?
Yes. While the backplane provides 5V DC for internal logic, the output circuitry requires an external 4.5-5.5V DC supply connected to the common +VDC terminal.

Q5: What types of loads are compatible with the 1746-OG16?
This output module drives TTL-compatible loads, including LED displays, logic-level solid-state relays, optocouplers, and other 5V DC sinking-input devices. Always verify load current remains under 24mA per channel.