Allen Bradley1771-OGTTL Output Module, 8 Point, 5 V DC Logic Level, 1771 I/O Chassis

Product Description

What this part is

Allen-Bradley 1771-OG TTL output module. Product Type: 5 V DC logic-level discrete output module for the 1771 I/O platform. Points: 8. Output Type: TTL. Output Voltage Low: 0 to 0.5 V DC. Output Voltage High: 2.7 to 5.25 V DC. Backplane Current: 168 mA at 5 V DC. Mounting Type: 1771 I/O chassis slot. Unit Quantity: 1 Pc.

Decoding the designation

1771 — the Allen-Bradley 1771 I/O platform, the rack-based I/O family served by PLC-2, PLC-3 and PLC-5 processors.

OG — the TTL output group within that platform, the logic-level counterpart to the 1771-IG TTL input module.

Electrical data

Points: 8. Output Voltage Low: 0 to 0.5 V DC. Output Voltage High: 2.7 to 5.25 V DC. Output Current Low: 20 mA sink. Output Current High: 1 mA. Output Filter: 1 ms. Backplane Current: 168 mA at 5 V DC. External Supply: 5 V DC ±0.25 V, 250 mA, 50 mV peak-to-peak maximum ripple. Power Dissipation: 2.2 W maximum. Thermal Dissipation: 7.5 BTU/hr maximum.

What these specs mean in practice

Output Type: TTL at standard logic levels. The module drives logic boards, indicator drivers and third-party electronics directly at 5 V, which is what a relay or triac output card cannot do.

Output Current Low: 20 mA sink. That is the standard TTL fan-out figure and it sets how many logic inputs one point will hold at a valid low.

External Supply: 5 V DC ±0.25 V at 250 mA, ripple held to 50 mV peak-to-peak. The field side runs off its own regulated supply, which keeps the logic reference separate from the chassis backplane and holds the output levels inside the TTL window.

Output Filter: 1 ms. The filter suppresses switching transients on the output line so a downstream logic gate does not see a false edge.

Backplane Current: 168 mA at 5 V DC. A modest chassis load, which goes into the 1771-P series supply budget alongside the rest of the rack.

Mounting data

Mounting Type: single slot in a 1771 I/O chassis. Terminations: removable field wiring arm. Controller Platform: PLC-2, PLC-3 and PLC-5 processors using the 1771 I/O structure.

Quantity and configuration

Unit Quantity: 1 Pc. One TTL output module.

Interchange guidance

Manufacturer Status: discontinued. Part Number: 1771-OG. MPN Variants: 1771OG, 1771 OG. The 1771-OGD is the 16-point TTL output module on the same logic levels, so it changes the point count and the chassis power budget. The 1771-IG is the 8-point TTL input module and the 1771-IGD the 16-point, forming the input side of the same logic-level pair.