The Allen-Bradley 1785-CHBM, also cataloged as the 1785-CHBM Backup Cartridge, operates as a dedicated hardware component for non-volatile program backup and memory retention within ControlNet PLC-5 systems.
Hardware Specifications
Parameter
Specification
Model
1785-CHBM
Brand
Allen-Bradley
Origin
USA / Global Manufacturing standard
Weight
0.40 lbs (0.18 kg)
Dimensions
Compact memory cartridge plug-in form factor
Operating Temp
0 to 60 deg C (32 to 140 deg F)
Power Consumption
Current load: 0.17 A at 5 VDC
Memory Capacity
100K EEPROM
Memory Type
Non-volatile EEPROM
Compatibility
Allen-Bradley ControlNet PLC-5 Processors
Lifecycle Status
Discontinued by Manufacturer
PLC-5 I/O Density Scaling & Backplane Bus Integration
The 1785-CHBM interfaces directly with ControlNet PLC-5 processor sockets to handle non-volatile logic backup. By maintaining 100K EEPROM non-volatile memory storage, the cartridge preserves active ladder logic and controller configurations across unexpected power interruptions. Operating at a backplane current draw of 0.17 A at 5 VDC, the module executes memory transfer routines during boot initialization without degrading backplane bus communication velocity across adjacent PLC-5 rack slots.
Frequently Asked Questions
Q: Can the 1785-CHBM backup cartridge be inserted or removed while backplane power is applied?
A: No. Inserting or removing the memory module while the CPU is powered can lead to EEPROM data corruption or system faults. Shut down chassis power prior to module extraction or insertion.
Q: How does the 1785-CHBM restore system memory upon controller initialization?
A: When configured in CPU parameters, the 1785-CHBM transfers its stored 100K EEPROM program image into processor RAM during power-up or upon detection of RAM memory corruption.
Field Installation Guidelines
Disconnect main AC power from the 1785 PLC-5 chassis and verify processor power LEDs are extinguished.
Wear a grounded anti-static wrist strap to prevent electrostatic discharge (ESD) damage to memory chips.
Locate the designated memory cartridge slot on the front face of the ControlNet PLC-5 processor module.
Align the 1785-CHBM module edge keyways with the socket guides and press firmly until fully seated.
Re-apply chassis power and confirm non-volatile memory detection using RSLogix 5 / 6200 programming software.
