Entron EN1000 series

ENTRON Controls, LLC. • 700120S • Page 117
Air over Oil Retraction is used on welding guns and stationary welders that incorporate special
air over oil cylinders. This function is only available in PROM firmware version 619016-002G
(or later).
This feature requires the use of three solenoid valve outputs. The first output (Valve 1) is assigned
to the extend solenoid. When the control is initiated, the extend valve is turned on, and the
electrodes will approach the work under low pressure. The intensify valve (Valve 2) is then
turned on once the electrodes reach the work and welding pressure is applied. The control
continues onto WELD time and HOLD time. At the end of HOLD time, both the extend and
intensify valves are shut off and a BLOCKING DELAY timer is then started. At the end of
BLOCKING DELAY, the blocking valve (Valve 3) is turned on. This valve is connected to the
extend port of the cylinder and when energized or closed, the return stroke can be halted before
the gun completely opens. Initiating the extend valve will de-energize the blocking valve.
AIR OVER OIL RETRACTION is available through EXTENDED FUNCTION
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Because of the longer time that is required for the electrodes to go from the fully retracted state
to the closed state, a SQUEEZE DELAY time is necessary. The SQUEEZE DELAY time is in
addition to any scheduled SQUEEZE time. The control will only go through SQUEEZE DELAY
when initiated from a fully retracted state. If the control is initiated when the blocking valve is
on, the control will not go through SQUEEZE DELAY.
RETRACTION TOGGLE
When the control is programmed for AIR OVER OIL RETRACTION, FS1 can be used as an
input to advance/retract the gun. When extending, the gun will advance during the programmed
SQUEEZE DELAY time (using Valve 1). Valve 1 will de-energize and ADVANCE STOP will
begin. Valve 3 will turn on immediately after the programmed ADVANCE STOP time
(programmed OFF time on schedule 00 in Figure 9-15).
The following steps assume that a blocking valve is connected between TS1-SV5 and TS1-SV6
(Valve 3 output):
1. Connect a normally open momentary close type switch between TS1-FS1 and TS1-GND.
2. Program SQUEEZE DELAY to time the advance of the gun to a ready position.
3. Program an OFF time in the first of the two schedules composing the weld sequence.
This OFF time is designated as ADVANCE STOP time. This time will only occur during
the FS1 toggle activation. It will not affect an actual weld sequence, since the first
schedule is a non-welding part of the sequence.
The timing of SQUEEZE DELAY (Step 2) and OFF/ADVANCE STOP (Step 3) is counted in
half cycle increments in order to double adjustment resolution.
To advance the electrodes, a momentary closure of FS1 will energize Valve 1.
The blocking valve will turn on immediately at the end of a programmed ADVANCE STOP
time. Travel distance will depend on SQUEEZE DELAY plus ADVANCE STOP. In addition,
inertia of the gun, oil pressure, etc., may influence travel distance.
9.5.3 AIR OVER OIL RETRACTION OPERATION –
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NOTICE