A-B-1756-RM-A- ControlLogix Redundancy Module (Series A)

Description

Key Technical Parameters

Slot requirement: Single‑slot mounting, fits any vacant slot on 1756 chassis Optical interface: LC single‑mode fiber connector, 100Mbps transmission speed; matched cable:1756‑RMC1 / 1756‑RMC3 Compatible CPU: ControlLogix 5570 series controllers (L61‑L64); not compatible with 5580 CPU and 1756‑RM2 mixed deployment Backplane consumption: 1.2A @5.1VDC; total power dissipation 9W Status indicator: PRI, COM, OK LED status lamps Supported software: Studio 5000 / RSLogix5000 Hot‑swap: Supported under non‑hazardous‑location condition Operating environment: 0‑60℃ cabinet‑mount installation, non‑condensing; UL, CE certification Note: Two‑piece 1756‑RM‑A are required for one complete redundant group; cannot interoperate with RM2 moduleRockwell A…

Practical Application Features

Real‑time mirroring for controller tags, I/O status and logic running state between main and standby racks. When primary rack fails, system triggers seamless switch‑over to standby rack to avoid production interruption. Module provides redundancy diagnosis tags, HMI can read synchronization status and fault information. Suitable for traditional continuous‑process industries: water treatment, petrochemical, power‑plant auxiliary control. Difference from RM2: This is old‑generation 100Mbps model; RM2 upgrades to gigabit fiber transmission.

Field Installation & Commissioning Guidance

Power‑off chassis before module insertion; lock front latch firmly after installation. Use Rockwell dedicated redundancy fiber cable, avoid sharp bending of optical fiber. Add 1756‑RM‑A into hardware configuration for both primary and standby projects. Keep firmware consistent for two RM‑A modules and paired CPU; inconsistent firmware will cause synchronization failure. Download identical application program to main‑standby controllers. Execute manual switch‑over test after commissioning, verify bumpless switching performance. Separate fiber wiring from high‑power cables, guarantee cabinet grounding quality.

In‑Site Troubleshooting Reference

1. OK LED off: Check chassis backplane power supply, module seating or internal hardware damage.
2. COM indicator no signal: Fiber cable damage, LC connector contamination, firmware mismatch between two redundancy modules.
3. Intermittent sync loss: Too small fiber‑bending radius, large optical attenuation, poor cabinet ground.
4. Fail to complete automatic switch‑over: Wrong redundancy parameter setting, main‑standby project program inconsistent.
5. Redundancy diagnostic alarm: Read internal fault code; check module firmware version and hardware configuration.
6. Hot‑swap trigger fault: Do not perform hot‑swap during formal redundancy running; follow official operation specification.