LINK Systems Omni II Automatic Setups Module - Manual (Page 75)

October 16, 2008 Manual Version 1.1
C-1
Appendix C Lockout Procedure For Air Controlled Systems
Section C.1 General Lockout Considerations
The OmniLink II Press Automation Automatic Setup module automatically controls pressures in
cushions and counterbalances. Because of this there are special considerations to keep in mind
when locking an air system out (at 0 pressure).
Note that cushions can be vented to zero pressure and the press will be allowed to run. A
counterbalance that has been vented to zero pressure, however, is considered a stop condition by
the press control.
While a type “A” valve has only integrated Fill/Dump valves, the type “B”, and “C” integrated
air valves (See Section 3.1 for a discussion of valve types) that Link uses to control air pressure
on cushions and counterbalances has a manual as well as an automatic section. The manual
section for these valves looks like a typical manual air pressure control with a regulator followed
by a check valve. There is a pressure gauge (“G1”) after the regulator but before the check
valve, and a gauge (“G2”) at the output air port after the check valve. When raising the pressure
by turning the manual regulator “up” the pressure forces the check valve open and gauge “G1”
will be approximately equal to gauge “G2”. However when lowering the pressure at the manual
regulator, the check valve will prevent the actual output pressure from going down (assuming
there are no leaks). A LOX valve on the output is used to blow down the system to lower the
pressure. In either case, gauge “G2” shows the true pressure in the counterbalance or cushion.
The automatic section of type “B” and “C” valves (and the only section of type “A” valves)
consists of a fill valve and a dump valve. A transducer mounted on the counterbalance surge
tank or cushion electronically reports the pressure of the system to the auto-setup board. If the
pressure is too low the fill valve puts more air in the system. If the pressure is too high the dump
valve vents air to atmosphere.
Section C.2 Valve Type “A” Lockout Procedure
To lock out type “A” valves:
1) Set the air pressure setpoint for the system to 0 psi. This will cause the control to
open the dump valve and leave it open to vent the system. Note that this valve will be
open only as long as the control is powered. If the system is set to 0 pressure, but the
control is turned off before the system can blow down, it will still be pressurized.
2) Use a LOX valve, if present, to dump the air system.
Note! Step 1 Must be done even if a LOX valve is opened in step 2 since
the control may try to pressurize to system using the Fill/Dump
valve if the power is on!