Publication 2364F-5.05 - March 1999
Troubleshooting The RGU
2-3
Unit Will Not Enable
After the disconnect lever and start switch have been turned on, the RGU
should power any connected HIM or GPT devices and perform its
precharge routine to raise the voltage of the capacitors on the DC bus.
If the Remote/Local Selector (P8) is set to ‘Local Only’, the RGU should
automatically enable when the precharge routine finishes. If the Remote/
Local Selector is set to ‘Local+Remote’, the RGU should enable when an
enable command is sent by a connected SCANport device (HIM, GPT,
etc.).
Check the following items if the unit will not enable.
Note: The RGU can also be enabled by setting the ‘Enable Cmd’ bit to 1
in the Host Command Word (P32).
Is the HIM/GPT screen illuminated?
Are there any faults indicated (on screen or
in the fault queue)?
Resolve the fault condition, clear the fault,
and reset the RGU (as necessary).
Do you want to enable the RGU with a HIM,
GPT, or other SCANport device?
Check the HIM/GPT and the cable. Test the
main control board. Replace as necessary.
No
Yes
Yes
Yes
No
Yes
Set the Local/Remote Selector to ‘Local Only’
(P8 = 0). Verify the ‘En at Pwr Up’ fault is
disabled (P180 bit 3 =0) and reset the RGU.
Did the unit pass the precharge routine?
Is M1 closed (or CB1 closed, for N-code RGU)?
Verify that the total capacitance on the DC bus
is within the precharge capability of the RGU.
Also, check P203 (External Capacitance).
No
Yes
Set the Local/Remote Selector to
‘Local+Remote’ (P8 = 1). Set the appropriate
bits in P224 and P225 to 1 (see example).
0100 0111
Example:
To enable Ports 1, 2, and 6, configure P224 (SCANport Port Enable Mask)
and P225 (SCANport Enable Mask) as shown.
Port 6
RGU I/O
Port 1
Port 2
No
Is a signal being applied to TB5-1 (Enable)
on the isolation board?
Check the RGU control circuitry and
other associated circuitry with the
system schematics.
No
