Allen-Bradley 1769-ASCII ASCII Module – 2 Ch RS232/RS485/RS422

1769-ASCII Communication Module – CompactLogix Series

Allen‑Bradley | 1769‑ASCII | 2‑channel RS‑232/RS‑485/RS‑422 ASCII interface

The 1769‑ASCII provides two independently configurable serial ports for ASCII devices. It supports full‑duplex RS‑232/RS‑422 and half‑duplex RS‑485, making it ideal for barcode readers, printers, and weighing scales.

Key Technical Features

• Two isolated ports – simultaneous operation with different protocols
• Hardware handshaking – RTS/CTS enabled for reliable data flow
• CompactLogix & MicroLogix 1500 – direct backplane connection
• Power supply distance rating – install within 4 modules of the power supply
• Diagnostic status – TX/RX FIFO overflow, parity error, handshake error

Technical Specifications

• Manufacturer – Rockwell Automation / Allen‑Bradley
• Model – 1769‑ASCII
• Product type – ASCII communication interface module
• Mounting – Chassis, DIN rail, or panel
• Power rating – 425 mA @ 5 V DC
• Power dissipation – 2.13 W (max)
• Thermal dissipation – 7.3 BTU/hr
• Backplane current – 1.4 A @ 24 V
• Isolation voltage – 30 V continuous (tested 710 V DC for 60 s)
• Input words – 108
• Configuration words – 31
• Serial signal voltage – 3…25 V DC (active) / -3…-25 V DC (inactive)
• Recommended cable – Belden 8761 (shielded)
• Operating temperature – 0 … 62 °C (32 … 140 °F)
• Storage temperature – -40 … 85 °C
• Relative humidity – 5 … 95 % (non‑condensing)
• Dimensions (H×W×D) – 118 × 87 × 34 mm
• Weight – 0.18 kg (0.4 lb)

Environmental & Mechanical Ratings

• Operating vibration – 5 g @ 10‑500 Hz
• Operating shock – 30 g
• Non‑operating shock – 50 g
• Pollution degree – 2 (IEC 60664‑1)
• Protection class – IP20

Diagnostics & Status Indication

• TX FIFO overflow – transmit buffer full alert
• RX FIFO overflow – receive buffer overrun
• RX parity error – framing or parity fault
• Handshake error – RTS/CTS mismatch
• New data flag – indicates fresh data available

Compatible Controllers & Systems

• Allen‑Bradley CompactLogix – 1769‑L1, L2, L3, L4 series
• MicroLogix 1500 – base unit or adjacent 1769 Compact I/O
• Any 1769 bus system – connects directly to backplane
• ASCII devices – barcode readers, printers, scales, RFID readers

Installation & Maintenance Guidelines

• Mount within 4 slots of the 1769 power supply for proper distance rating
• Use shielded Belden 8761 cable for RS‑485 networks
• Configure ports independently as RS‑232, RS‑422, or RS‑485
• Set handshaking (RTS/CTS) via software or DIP switches
• No external power required – backplane powered

Certifications & Compliance

• CE mark – EN 61010‑1, UL 61010‑1
• cULus – Class I, Div. 2 hazardous locations
• ATEX Zone 2 – compliant for explosive atmospheres
• RoHS & WEEE – fully compliant
• Marine – ABS, BV, DNV, LR approved

Oiltech Controls’s Insight

• Most field issues come from incorrect cable shielding – always use Belden 8761.
• Set RTS/CTS handshake when connecting to legacy printers to avoid data loss.
• For long RS‑485 runs ( >100 m ), terminate the line with 120 Ω resistor.
• Use port 1 (RS‑232/422) for high‑speed barcode scanners; port 2 (RS‑485) for multi‑drop networks.
• Check parity and baud rate – mismatches are the #1 startup problem.

Frequently Asked Questions (FAQ)

• Can I use both ports at the same time with different protocols?
  Yes – each port is independently configurable. You can set port 1 as RS‑232 and port 2 as RS‑485 simultaneously.
• What is the maximum cable length for RS‑485 on this module?
  With Belden 8761, you can achieve up to 1200 m (4000 ft) at 100 kbps. For longer runs, reduce baud rate.
• My barcode reader works intermittently – what should I check first?
  Verify handshaking (RTS/CTS) and cable shielding. Also, ensure the reader’s baud rate matches the module’s configuration.
• How do I know if the module is properly powered?
  The module draws power from the backplane. Check the green “OK” LED. If it’s off, verify the power supply distance rating (within 4 slots).
• Can I use this module with a MicroLogix 1500 without an external supply?
  Yes – it’s backplane powered. Just plug it into the base unit or an adjacent 1769 module.

Why Buy From Oiltech Controls?

• 15+ years – deep expertise in industrial automation spares
• Worldwide shipping – FedEx, UPS, or DHL express
• Tested options – surplus and refurbished units fully verified
• 12‑month warranty – comprehensive coverage
• Pre‑shipment verification – every unit tested before dispatch
• Legacy support – we help with obsolete control systems

Contact our team: info@oiltechcontrols.com | +86 158 8020 0923

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Dispatch – within 24‑28 hours (business days)
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Warranty – 12 months from delivery date

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