1785-L40B

Technical specifications

Manufacturer

Allen-Bradley

Manufacturer part no.

1785-L40B

Type

PLC-5 processor

Application

PLC controller

Used with

1771 I/O chassis (leftmost slot)

Processor

PLC-5/40

Maximum user memory (words)

48K

Total I/O, maximum

2048 any mix or 2048 in + 2048 out (complement)

Channels

4 DH+/remote I/O

I/O chassis, maximum total

61

Remote I/O chassis, maximum

32 max/link

Power dissipation, maximum

17.3W

Backplane current load

3.3A

Operating temperature

0...60 °C (32...140 °F)

Storage temperature

-40...85 °C (-40...185 °F)

Relative humidity

5...95% noncondensing

Vibration

2 g @ 10...500 Hz

Shock

Operating 30 g; non-operating 50 g

Enclosure type rating

None (open style)

Time-of-day clock/calendar

Maximum variation at 60 °C: ±5 min per month; typical at 20 °C: ±20 s per month

I/O modules

Bulletin 1771 I/O, 1794 I/O, 1746 I/O, and 1791 I/O, including 8-, 16-, 32-pt and intelligent modules

Hardware addressing

2-slot, 1-slot or 1/2-slot

Location

1771-A1B, -A2B, -A3B, -A3B1, -A4B chassis; leftmost slot

Replacement battery

Allen-Bradley 1770-XYC

Available cartridges

1785-RC Relay Cartridge

Memory modules

1785-ME32, 1785-ME64, 1785-M100

Communication

Serial; DH+; DH using 1785-KA; remote I/O

Isolation voltage

Communication ports tested to 500V for 60 seconds

Weight

3 lbs, 2 oz (1.42 kg)

Technical documents (1)

• Rockwell Automation publication 1785-IN062 (specifications)

Key features

• Supports up to 61 I/O chassis in total
• Supports up to 32 remote I/O chassis per link
• Accepts 1785-ME32, 1785-ME64 and 1785-M100 memory modules
• Serial, DH+, DH using 1785-KA, and remote I/O communication
• Communication ports tested to 500V for 60 seconds

About the Allen-Bradley 1785-L40B

The Allen-Bradley 1785-L40B is a PLC-5 processor, the PLC-5/40, according to Rockwell. Rockwell publication 1785-IN062 gives maximum user memory of 48K words, total I/O of 2048 any mix or 2048 in + 2048 out (complement), and 4 DH+/remote I/O channels. The same publication lists a maximum of 61 I/O chassis, 32 remote I/O chassis per link, power dissipation of 17.3W and a backplane current load of 3.3A. Rockwell Product Lifecycle Search shows it as discontinued on 31 December 2014, with the replacement category Engineering Replacement.

What is the 1785-L40B used for?

The 1785-L40B is the processor in a PLC-5 system, fitted in the leftmost slot of a 1771-A1B, -A2B, -A3B, -A3B1 or -A4B chassis. It works with Bulletin 1771, 1794, 1746 and 1791 I/O, including 8-, 16-, 32-pt and intelligent modules, using 2-slot, 1-slot or 1/2-slot hardware addressing. It communicates over serial, DH+, DH using 1785-KA, and remote I/O.

Lifecycle and successor

Discontinued.

Before you order

What to photograph or confirm so the right unit is quoted.

Check that the label reads catalog number 1785-L40B, and note the series letter and firmware revision printed on it. Send us a photo of the label so we can check it against your requirement.