Recovery From Blown Fuse/Processor Fault/Processor Shutdown; Replacement Fuse Recommendations - Allen-Bradley 1746-IA4 Installation Instructions Manual

14 Digital I/O Modules
This table defines operation of all SLC 500 processors in the case of a blown fuse in
1746-OBP16, 1746-OVP16, and 1746-OAP12 modules.
.
Processor Operation After a Blown Fuse (1746-OBP16, 1746-OVP16, and
1746-OAP12 modules)
JP1 Set to
Processor Continues
No error. Processor continues with 1746-OBP16 and 1746-OVP16
outputs de-energized. 1746-OAP12 outputs, on the same
common as the blown fuse, are de-energized.

Recovery From Blown Fuse/Processor Fault/Processor Shutdown

Processor operation will stop under the following conditions:
• The output module fuse blows due to a short circuit.
• JP1 is set to the Processor Faults position (pins 2 and 3 connected).
If the above conditions occur, the following procedures should be used for
recovery.
1. Follow fuse replacement procedures shown on page 15.
2. Clear the processor major fault bit S:1/13.
3. Clear processor status file S:6 major error code (optional).
4. Return the processor to Run mode.
For additional information on processor fault codes and clearing processor fault
bits, refer to the following user manuals:
• Your programming device's reference manual
• HHT User Manual, publication 1747-NP002
– Chapter 28, Troubleshooting Fault
– Chapter 29, Understanding the Fault Routine

Replacement Fuse Recommendations

Use the following replacement fuses:
• 1746-OBP16 and 1746-OVP16 modules - Littelfuse #322010,10A or
#332010,10A. This fuse is required to maintain UL/CSA rating. Replacement
Fuse Kit is catalog number
1746-F8 (five fuses per kit).
Publication 1746-IN027C-EN-P - August 2008
JP1 Set to
Processor Faults
Nonrecoverable error. Processor
operations stop and all outputs reset to
OFF.