20 Gear Drive, Plymouth Industrial Park, Terryville, CT 06786 page: 19
Tel: (860) 585-1254 Fax: (860) 584-1973 Web: www.amci.com
ControlLogix 7252 LDT Interface Manual
Revision 1.5
Chapter 7: Input & Output Data
Input Registers: (Data sent from the 7252 module to the PLC)
The input data consists of five (for 1 channel) or ten (for 2 channels) 32-bit words, and is read by the PLC at the RPI
(Requested Packet Interval) Time that is asynchronous to the Ladder Logic Program. The Input data will be referenced
as Local:X.I.Data[Y] where “X” is the slot number and “Y” is the word number.
To ensure that the same data is used throughout the entire PLC program, this data should be buffered to internal
registers at one place in the program. However, in order to take advantage of the real time availability of the
Interpolation Data value, the Interpolation Acknowledge bit, the Limit Switch State Bit, and the Interpolation Limit
Switch State Bit should be used directly from their respective Input Registers.
The data contained in the input registers consists of Status Word, Data Value, Velocity and any associated Latched or
Interpolated Data Values.
Input Data for the 1 Channel Configuration
Channel
Number
32 Bit
Word
Function
Units
1
0
Status Word1
See descripiton below
1
Data Value 1
Counts
2
Velocity 1
Counts / Second
3
Latched Data Value 1
Counts
4
Interpolated Data Value 1
Counts
Input Data for the 2 Channel Configuration
Channel
Number
32 Bit
Word
Function
Units
1
0
Status Word 1
See descripiton below
1
Data Value 1
Counts
2
Velocity 1
Counts / Second
3
Latched Data Value 1
Counts
4
Interpolated Data Value 1
Counts
2
5
Status Word 2
See descripiton below
6
Data Value 2
Counts
7
Velocity 2
Counts / second
8
Latched Data Value 2
Counts
9
Interpolated Data Value 2
Counts