PRODUCT INFORMATION
Product Overview
The Allen-Bradley 1785-L40B is a PLC-5 standard processor controller module. It mounts directly into an approved 1771 I/O chassis. Compatible chassis models include 1771-A1B, 1771-A2B, 1771-A3B, 1771-A3B1, and 1771-A4B. The processor features 48 kilowords of battery-backed static RAM user memory. It addresses up to 2048 total I/O points in standard or complementary arrangements.
This controller provides four configurable Data Highway Plus or Universal Remote I/O combination ports. It also includes one serial port supporting RS-232, RS-422A, and RS-423 standards. Up to 29 total chassis can operate in standard network configurations. The architecture supports one local chassis and up to 28 Universal Remote I/O chassis. Optional 1785-ME series EEPROM modules supply non-volatile backup memory.
TECHNICAL DATA
Technical Specifications
| Parameter | Specification |
|---|
| UPC | 612598124015 |
|---|
| Weight | 3.44 lbs (1.56 kg) |
|---|
| Non-Operating Temperature | IEC 60068-2-1 (Test Ab, Un-packaged Nonoperating Cold), IEC 60068-2-2 (Test Bc, Un-packaged Nonoperating Dry Heat), IEC 60068-2-14 (Test Na, Un- packaged Nonoperating Thermal Shock): –40...85 o C (– 40...185 o F) |
|---|
| Operating Temperature | EC 60068-2-1 (Test Ad, Operating Cold), IEC 60068-2-2 (Test Bd, Operating Dry Heat), IEC 60068-2-14 (Test Nb, Operating Thermal Shock): 0...60 o C (32...140 o F) |
|---|
| Maximum number of I/O per link | 32 |
|---|
| Battery | 1770-XYC |
|---|
| Memory | 48 KWords |
|---|
| Embedded Communication interfaces | 4 DH+/Remote I/O (Adapter or Scanner) 1 serial port, configurable for RS-232 and 423 and RS-422A standards |
|---|
| Backplane current load | 3.3A |
|---|
| Power Dissipation | 17.3W |
|---|
| Power Supply | 1771-P4S, -P6S, -P4S1, -P6S1 |
|---|
| Module Type | Standard Processor |
|---|
| Processor | PLC-5/40 |
|---|
| Max User Memory Words | 48 Kilowords |
|---|
| Battery-Backed Static RAM | Yes |
|---|
| EEPROM Program Backup Option (using 1785-ME16, -ME32, -ME64, and -M100) | Yes |
|---|
| Protected Memory | No |
|---|
| Max Total I/O | 2048 (any mix) or 2048 in + 2048 out (complementary) |
|---|
| Max Analog I/O | 2048 |
|---|
| I/O Scan Time Per Rack | 10 ms at 57.6 kbits/s, 7 ms at 115.2 kbits/s, 3 ms at 230.4 mbits/s |
|---|
| Max I/O Chassis Total | 61 |
|---|
| Max I/O Chassis Extended Local | 0 |
|---|
| Max I/O Chassis Universal Remote | 32 Max. Per I/O Link |
|---|
| RS-232-C/422-A/423- A Ports | 1 |
|---|
| Control Coprocessor Expansion Port | Yes |
|---|
TECHNICAL INFORMATION
Features
- Integrated 48 kiloword battery-backed static RAM internal storage capacity.
- Controls up to 2048 total I/O points in standard or complementary modes.
- Four combination ports configurable for Data Highway Plus or Universal Remote I/O.
- One serial channel supporting RS-232, RS-422A, and RS-423 standards.
- Dedicated Control Coprocessor Expansion Port for modular system growth.
- Program backup support via optional 1785-ME series EEPROM memory modules.
- Certified operating temperature range from 0 to 60 degrees Celsius.
TECHNICAL INFORMATION
Applications
- Medium to large-scale industrial process control automation installations.
- Distributed manufacturing architectures using Universal Remote I/O networks.
- Plant supervisory networks communicating over Data Highway Plus links.
- Industrial facilities utilizing standard 1771 I/O chassis systems.
TECHNICAL INFORMATION
Connections / Interfaces
- Four communication channels configurable for DH+ or Universal Remote I/O operation.
- One serial port supporting RS-232, RS-422A, and RS-423 protocols.
- One dedicated Control Coprocessor expansion interface connector.
- Direct backplane interface drawing 3.3 A from the host chassis.
TECHNICAL INFORMATION
Installation Guidelines
- Mount the processor into an approved slot inside a compatible 1771 chassis.
- Verify the chassis power supply satisfies the 3.3 A backplane current requirement.
- Maintain operating ambient temperatures between 0 and 60 degrees Celsius.
- Connect a 1770-XYC lithium battery to maintain static memory retention.
TECHNICAL INFORMATION
Configuration Guidelines
- Assign each combination port to Scanner or Adapter mode as required.
- Configure individual communication baud rates to meet target scan time metrics.
- Insert an optional 1785-ME EEPROM module for non-volatile application backup.
TECHNICAL INFORMATION
Compatibility
- 1771-A1B, 1771-A2B, 1771-A3B, 1771-A3B1, and 1771-A4B I/O chassis.
- 1771-P4S, 1771-P6S, 1771-P4S1, and 1771-P6S1 power supply modules.
- 1770-XYC lithium battery.
- 1785-ME16, 1785-ME32, 1785-ME64, and 1785-ME100 memory modules.
TECHNICAL INFORMATION
Compliance and Certifications
- IEC 60068-2-1
- IEC 60068-2-2
- IEC 60068-2-14
COMPATIBILITY
Compatibility & Replacement
COMPATIBLE MODELS1771-A1B, 1771-A2B, 1771-A3B, 1771-A3B1, and 1771-A4B I/O chassis. 1771-P4S, 1771-P6S, 1771-P4S1, and 1771-P6S1 power supply modules. 1770-XYC lithium battery. 1785-ME16, 1785-ME32, 1785-ME64, and 1785-ME100 memory modules.
Verify compatibility against the exact Part Number, revision and manufacturer documentation before ordering.
PART VERIFICATION
Before You Order
Industrial automation parts can share similar model names, suffixes and revisions. Confirm the complete manufacturer Part Number before purchase.
01Check Part NumberMatch the complete ordering code on the existing unit.
02Confirm RevisionCheck suffix, hardware or firmware when applicable.
03Send a Label PhotoWe can review a clear label photo when identification is uncertain.
ORDERING PROCESS
From RFQ to Dispatch
1Submit Part Number2Verify Product Identity3Confirm Stock & Condition4Issue Quotation5Dispatch & Tracking
PRODUCT FAQ
Frequently Asked Questions
What is the memory capacity of the Allen-Bradley 1785-L40B?
The 1785-L40B contains 48 kilowords of battery-backed static RAM user memory.
What communication interfaces are built into the 1785-L40B controller?
It includes four DH+ or Remote I/O combination ports and one configurable serial channel.
Which power supplies are compatible with the 1785-L40B system?
Supported chassis power supply models include 1771-P4S, 1771-P6S, 1771-P4S1, and 1771-P6S1.
