Applicable Systems
EFC
FEX
FEI
HNC
Symptoms
+/-15V supply fault. The internal +/-15V DC power supply rail for analog circuits is out of specification. Analog inputs and encoder signal conditioning may be affected.
Possible Causes
- Internal power supply component failure on control board
- Short circuit on the +/-15V rail from external wiring
- Control board component degradation
- Power supply overload from too many analog sensors
Troubleshooting Steps
- Step 1: Check all external analog input/output wiring for short circuits
No continuity between analog signal wires and ground or each other - Step 2: Disconnect all external analog devices and restart the drive
If F8069 clears, an external device was loading the +/-15V rail - Step 3: If F8069 persists with no external load, the internal power supply has failed
Control board replacement required - Step 4: Replace control module
New module provides stable +/-15V rails
How to Reset
1) Disconnect all analog I/O. 2) Restart drive. 3) If fault clears, find and fix the shorted external device. 4) If fault persists, replace control module.
Frequently Asked Questions
- Q: What devices use the +/-15V supply?
Analog sensors (pressure, temperature, position), analog command signals (0-10V, 4-20mA), and encoder signal conditioning circuits.
- Q: Can I test the +/-15V rail?
With the drive powered on and external loads disconnected, measure between the +/-15V test points on the control board. Readings should be within +/-0.5V of nominal.
Source: Rexroth IndraDrive HCS/HMS Fault Code List, Bosch Rexroth AG
Category: PLC & VFD