What the 1756-CPR2 Does in a ControlLogix Rack
Downtime in a ControlLogix chassis rarely comes from the processor. It comes from the small, easy-to-overlook link between the redundant power supply and the chassis adapter. The Allen-Bradley 1756-CPR2 is exactly that link: a 0.91 m (3 ft) Redundant Power Supply Cable built to connect a Redundant Power Supply to the 1756-PCSA2 Chassis Adapter.
Rockwell Automation lists this cable under the ControlLogix series. It carries a configuration of Redundant, so it belongs to systems where a second supply backs up the first. Without a correct, intact cable in that position, the backup path simply is not there.
Key Parameters at a Glance
The 1756-CPR2 is a passive connection item, but its electrical figures matter when you plan a redundant rack.
| Parameter | Value |
|---|---|
| Series | ControlLogix |
| Configuration | Redundant |
| Cable Length | 0.91 m (3 ft) |
| Input Current | 970 mA at 5.1 VDC; 1.7 mA at 24 VDC |
| Power Dissipation | 5.1 Watts |
| Thermal Dissipation | 17.4 BTU per Hour |
| Slot Width | 1 |
| Weight | 0.64 lb (0.293 kg) |
Those current figures tell a practical story. The 970 mA draw at 5.1 VDC is the dominant load, while the 1.7 mA at 24 VDC is minimal. Power dissipation of 5.1 Watts and thermal dissipation of 17.4 BTU per hour are small, so the cable adds little heat inside an already warm enclosure. A single slot width keeps the routing compact.
Where This Cable Fits
Redundant power is common in oil, gas, and continuous-process plants where a supply trip should not stop the controller. In those cabinets, the 1756-CPR2 sits between the redundant supply and the 1756-PCSA2 adapter, completing the backup path.
It also suits retrofit work. When a rack is upgraded to a redundant supply arrangement, this cable is one of the parts that must match the chassis adapter exactly. Using the correct 3 ft length keeps cable dress clean and avoids strain on the adapter connector.
Fitting and Care
Mounting is straightforward: route the cable between the redundant power supply and the 1756-PCSA2 Chassis Adapter, keeping the bend radius gentle and the run clear of moving parts. The stated operating temperature range is 0 to 60 °C (32 to 140 °F), so keep cabinet airflow within that band.
During routine inspections, check the connectors for tightness and look for abrasion along the jacket. A loose or damaged cable can silently remove redundancy, which is the failure you will not notice until the primary supply drops. Replace suspect cables before the next planned outage rather than during one.
Before You Order
Confirm three things: the rack uses a redundant power supply, the chassis adapter is a 1756-PCSA2, and the required run is 0.91 m (3 ft). If your layout needs a different length, do not force this part.
Please verify current lifecycle status and availability with Oil AutoTech before ordering. Oil AutoTech supplies ready-to-ship ControlLogix spares and offers hands-on technical selection help, so you can match the cable to your chassis correctly the first time. Contact Oil AutoTech today for pricing and availability.
