On March 29, 2017, a 9 tonne steel shield block was transferred from the ARIEL Target Pit and placed into a 
wood container on the Target Hall B1 level with the overhead crane main hoist in Local Mode without incident. 
Afterwards, the overhead crane was switched into Test Mode (which is the same as Remote Mode but without the 
Target Hall interlocked) and an attempt was made to transfer the shield block from the wood container on the B1 
level to a wood container in the Target Pit remotely with the main hoist. At 11:51:09, after lifting the shield 
block ~1 m above the B1 level, a "136. Main Hoist West Drum South Motor Drive Fault (900 VFD)" alarm pop-up was 
shown on the overhead crane HMI in the crane control room which disabled the controls on the remote console. 
The reset button on the remote console was pressed and the remote lifting operation was resumed briefly until 
the same fault occurred at 11:51:42 and the reset button was pushed once again. While attempting to lower the 
shield block back down to the ground this fault-reset sequence reoccurred at 11:57:25, 11:58:16, 11:58:28, 
11:58:43, 11:59:27, and 12:00:27, at which point the remote crane operation was aborted and the shield block 
was lowered down to the Target Pit floor with the main hoist in Local Mode, without incident. The Test Mode 
faults did not appear to depend upon the speed/acceleration of the lift, nor did they appear to be spaced apart 
by a fixed time interval. Upon closer inspection of the alarm history screen in the HMI (shown below) and the 
exported alarm log (attached below), almost every time the fault #136 occurred, the following three additional 
faults were logged simultaneously in the alarm history (but were not displayed as a pop-up on the main HMI 
screen):
"103. Main Hoist East Drum North Motor Drive Fault (700 VFD)" 
"104. Main Hoist East Drum South Motor Drive Fault (800 VFD)" 
"135. Main Hoist West Drum North Motor Drive Fault (1000 VFD)" 

On March 31, 2017, the overhead crane main hoist was operated once again in Test Mode; however, no load was 
connected to the hook block to determine if the faults that occurred two days earlier could depend on the load. 
The main hoist hook block was remotely lowered ~3 m below the upper 'home' position, and then remotely raised 
as high as possible to function test the upper limit switch in remote mode; at 14:21:05 immediately after 
initiating the 'hoist up' motion, the same four faults occurred simultaneously. This incident shows that these 
specific faults do not depend on what load is connected to the hook block. Note: the crane position data from 
March 31 is attached below, however the times shown are 1 hour fast due a DST adjustment error.

Follow up with the crane supplier, COH, is required to obtain a index and troubleshooting guide for these (and 
all other) fault codes.

2017-04-06 update: Sylvain Raymond of COH has been assigned to resolve these crane faults by Maxime Dubé-Blanchet 
of COH.