Product Description
2
0
1
8
-0
6
13
2.2.3
Enhanced ZPA
This operating mode implements zero pressure accumulation with block accumulation or block
release. A zone will let the following conveyed product enter once the conveyed product
located in that zone receives the release signal to leave the zone. This reduces the safety
distance between the conveyed product and increases the throughput. If the foremost zone of
such an accumulation conveyor line receives a release signal, the signal will be forwarded
directly to the zones behind it. All accumulated conveyed product will be simultaneously
transported to the next zone. However, in case of block release, it is always ensured that only
one further conveyed product is conveyed into the zone. This conveyed product must then
advance all the way to the zone sensor before the next conveyed product may be conveyed.
The following example describes the sequence in the operating mode "Enhanced ZPA."
Figure 2.8
■
Step A: Zone (2) has accumulated its conveyed product because downstream zone (3)
has not set its release signal (red light). Because zone (2) is occupied, it also does not
issue a release to upstream zone (1).
■
Step B: Downstream zone (6) has set the release signal (green light) and the conveyed
product is conveyed to the next zone (6). At the same time, the release signal is forwarded
to upstream zone (4) and the following conveyed product is conveyed to zone (5). The
conveyed product starts up at the same time.
■
Step C: The previous conveyed product has departed zone (8), so downstream zone (9)
withdraws its release. The following conveyed product has also already left upstream
zone (7). Zone (8) moves the conveyed product to its zone sensor while it prevents other
conveyed product from entering by resetting the release.
The following time conditions are used in the operating mode "Enhanced ZPA" (see Chapter
"Operating Behavior"):
■
Leaving time
■
Entry time
■
Transportation time
■
Motor run-on time
■
Switch-on delay
■
Search time
■
Release delay
Please note that this operating mode distinguishes between 1-zone operation and 2-zone
operation and separate settings exist for both operating modes.
5
6
4
B
2
3
1
A
8
9
7
C
Roller motor
Zone sensor
Zone sensor
Roller motor
Zone sensor
Zone sensor
Roller motor
Zone sensor
Zone sensor
