User Manual

Programming 5-7
5.6.1.3 Periodic Behavior
Periodic behavior is defined by the instructions in the Periodic procedures. These procedures allow a
sequence of operations to be performed periodically during production. The procedure names are reserved
and can only be used for periodic behavior. Periodic procedures are named Periodic, Periodic1, Periodic2,
Periodic3, etc.
A Periodic procedure is executed when its periodic timer expires. Periodic Timers can be configured to
execute on an elapsed-time (seconds) or number-of-products-coated (count) basis. Only an error or
operator-initiated stop prevents a periodic procedure from executing. Periodic behavior is commonly used
to purge the dispenser nozzle during production in order to prevent material from curing in the nozzle.
 NOTE To execute periodic procedures, the Periodic Timers must be set. See 4.15.2 Setting
Periodic Timers.
5.6.1.4 Product-Specific Periodic Procedure
Periodic procedures can be placed in either a product program or a macro program. If the instructions in a
periodic procedure are used with more than one product program, place the periodic procedure in a macro
program and load the macro program before running the product programs. If the instructions in a
periodic procedure are product-specific, place the periodic procedure in a product program rather than the
macro program:
 Only one periodic procedure can exist in a macro program for each timer.
 Only one macro program can be loaded at a time.
 Production must be stopped and the Edit Screen opened to load a new macro program.
ECXP looks for periodic procedures in the product program first, and then in the currently loaded macro
program. If you place a periodic procedure in the product program, it is executed and any periodic
procedure with the same name in the macro program is ignored.
Exercise 5-2: Using Periodic Procedures to Purge the Dispenser Nozzle
You want to move the nozzle over a purge cup and perform a purge. The purge cup is mounted on the
moving conveyor rail. Most of the products are 6-inches wide, however a few are 4-inches wide. Because
the cup changes position when the conveyor rail moves to accommodate the different product widths, you
need one procedure for the 6-inch products and another for the 4-inch products. How can you change
procedures without stopping production and loading a new macro program?
Solution: Put the periodic procedure for the 4-inch wide products in their product program. Put the
periodic procedure for the 6-inch wide products in the macro program. ECXP will use the periodic
procedure in the macro program for all 6-inch wide products. When the product program for a 4-in wide
program is run, the periodic procedure in the product program will be used instead of the one in the macro
program because ECXP looks for procedures in the product program first.