Rockwell Automation 4100 AEC Absolute Encoder Converter Installation - Manual (Page 57)

Publication 4100-UM052B-EN-P - October 2001
Strobe Position For Applications Not Using the 1394 or Compact 49
input on the AEC. Internally the AEC, holds it high when inactive and
to activate, it must be connected and pulled low. Within 30ms (tph)
of the strobe going active, the encoder output A and B signals are
held at their current state (any incremental updating is prohibited).
On Ts1 going inactive, the lower 16 bits of the absolute position is
transmitted. Anywhere from 0 to 65535 counts can be transmitted. It
can take up to 25ms (Ts1hpe) to transmit the least significant word
(LSW) of the transducer position. After the LSW has been transmitted,
the second strobe (Ts1s2) is brought active.
When the second strobe goes inactive (ts2), it triggers the
transmission of the most significant word (MSW). Anywhere from 0 to
511 counts can be transmitted. This completes an absolute position
update cycle. Once the MSW has been sent(Tpei), the AEC begins
sending incremental changes (Free-Running) or the Encoder output
remains inactive as the AEC waits for an incremental strobe pulse
(Locked).
Incremental Strobe Period When using controlling hardware other than the 1394 or Compact, it is
recommended that you set the Configuration Switch B for Free Run
operation (see Chapter 3, Setup). In this mode position, changes from
the transducer are sent every 1/1000
th
second by the AEC via the
encoder port (see Chapter 4, Operation at Startup). If synchronization
of incremental position updates is required by your application, the
controller hardware must be capable of generating periodic strobe
pulses as described in this section. The following diagram and table
outline the parametric requirements for an incremental strobe period.
Figure 19 Incremental Strobe Period Protocol
Strobe
Quadrature
Pulse Train
Tinc
Ts1 Ts1s1
Ts1pe
Position Increment
Delta Counts