Specifications

Positioning IP 240
b) Switching and signalling ranges for a position
During the approach to a target position, the IP 240 monitors the entry into ranges BEE1
and BEE2 in order to be able to control the drive. Overtravel and standstill of the axis after
the drive has been switched off, however, must also be considered. You can define a tar-
get range (BEE3) for this purpose. The IP 240 signals entry into and exiting of this range via
status bits and interrupts.
You must define all three ranges over their distance to the position value. The resulting
ranges are symmetrical to the target position.
Fig. 10-4. Setting up a Position
Distance values of the
switching and signalling ranges
BEE1 BEE3
BEE3 BEE2 BEE1
Target position
BEE2
Range BEE3
Range BEE2
Range BEE1
The specified distance values apply for all positions stored on the IP 240. The following must
be observed when defining the distance values:
Distance value to range BEE1 distance value to range BEE2 distance value to range BEE3.
c) Approaching a position
To invoke one of the positions 1 to 254 you need only forward the position number to the
IP 240. The IP takes the value stored under this position number as the new position value and
updates the status bits in accordance with the current actual value.
Each of the BEE ranges (1, 2 and 3) is assigned a status bit, which is
• set to ”1” when the actual value is out of range and
• set to ”0” when the actual value is in range or at a range limit.
The direction bit (RICH) indicates the direction in which the actual value must be modified in
order to reach the target position.
• If RICH=0, traverse must be in a positive direction (ascending actual value).
• If RICH=1, traverse must be in a negative direction (descending actual value).
Note that both IP outputs must be disabled when a position between 1 and 254 is selected.
Once the position has been selected, the outputs are set in dependence on the actual value.
10-4 EWA 4NEB 811 6120-02a