Troubleshooting Blank Screen / Display; Temporarily Switching From Closed Loop To Open Loop - Hitachi P1 Basic Instruction Manual

TR OUB LE S HO O TIN G B LA N K SC RE E N / D I SP L AY
If the VFD's screen / display is blank it usually means the internal 24v power supply is shorted or damaged. In most cases if a
connected circuit is causing the short, disconnec�ng that circuit will restore 24v power to the screen / display.
• Check for power on the VFD's L1 and L3 input power terminals.
• Disconnect the encoder wires from the VFD's main body control circuit terminals A, B, COM, CM1.
• Disconnect all wires from the VFD's main body control circuit terminals related to 24v, (COM, P24, P-, P+, CM2)
• Contact Detroit Hoist for further assistance.
TE M P OR AR I LY S W IT C HI N G F RO M C LO SE D LO O P TO O PE N L OO P
In the case of an encoder failure, it might be required to switch from closed loop to open loop in order to lower a load.
DO NOT con�nue to operate the hoist in open loop mode unless for troubleshoo�ng purposes without a load suspended.
Opera�ng a closed loop hoist in open loop mode other than for the purpose of troubleshoo�ng without a load suspended or
lowering a load is HIGHLY DISCOURAGED since all safety features will be disabled.
open loop mode with a load suspended or the load may fall, use other means to remove suspended load.
To switch from closed loop to open loop change parameter AA121 = 08 SLV for high torque output and power cycle the VFD.
No other parameters are required to be changed. All safety func�ons will be bypassed automa�cally, and the encoder limit
func�ons will be ignored. The brake release circuit will be switched over to the open loop brake control using brake release and set
frequencies.
Function
VFD Control Mode
IMPORTANT! – If an E51 fault was occurring, DO NOT switch to open loop mode with a load suspended or the load may fall, use
12/17/2018 Hitachi P1 Closed Loop Hoist Basic Instruc�on Manual Firmware V19 – V25
Parameters
AA121
other means to remove suspended load.
If an E51 fault was occurring, DO NOT switch to
Value
10: Closed Loop Vector
08: Open Loop SLV
24