AMCI NXEE2, User Manual

Page: 13 / 74

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
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NXEE2 User Manual
I
NTRODUCTION TO THE
NXEE2
13
NXEE2 Programmable Parameters (continued)
Channel Setup Parameters (continued)
Network Input Data Format
The following values can be transmitted to the host controller in the Network Input Data:

Data Value

Velocity

Captured Data Value

Actual SSI Data
There are only five data words available to each channel. Therefore the NXEE2 can only transmit two values
at a time. The Network Input Data Format parameter allows you to choose which values are transmitted.
The NXEE2 can take up to four milliseconds to accept a change in format and begin transmit-
ting the newly selected values. If your network interface updates the Network Input Data at a
rate faster than four milliseconds, it may take multiple reads before the change in selected val-
ues is seen.
Programming Cycle
New parameter values are written to the NXEE2 through a Programming Cycle. A Programming Cycle con-
sists of six steps and is controlled by the Transmit Bit in the Network Output Data and the Acknowledge Bit
in the Network Input Data.
1) Write the new programming data into the registers assigned to the module with the Transmit Bit
reset. This step insures that the correct data is in the registers before the Programming Cycle begins.
2) Set the Transmit bit. A Programming Cycle is initiated when this bit makes a 0

1 transition.
3) Once the NXEE2 is done with the programming data, it will set any necessary error bits and the
Acknowledge Bit in the Network Input Data.
4) Once you see the Acknowledge Bit set, check for any errors. The error bits are guaranteed valid
while the Acknowledge Bit is set.
5) Respond to any errors and reset the Transmit Bit.
6) The NXEE2 responds by resetting the Acknowledge Bit. The Programming Cycle is now complete.
All parameters are checked before any of them are applied. If there is an error in the block of
data, the NXEE2 will only set the appropriate error bits in the Network Input Data. Parameters
are not applied to the NXEE2 until all of the data is correct.