Rockwell Automation 1734-IK Encoder/Counter Modules User Manual - Manual (Page 34)

Publication 1734-UM006B-EN-P - August 2005
3-2 Input and Output Data
Detailed Description of
Data Table Information Present Channel Data (Input Word 1)
This is a 32 bit unsigned long word value representing the current
count of the 24 bit counter (configurations: count [0], x1 encoder [1],
x2 encoder [2], x4 encoder [4]) or the frequency (configurations:
period/rate [5], rate measurement [7]). The range of values is 0
≤ value
≤ 0x00FFFFFF (16,777,215).
Stored/Accumulated Channel Data (Input Word 2)
This is a 32 bit unsigned long word value representing the stored
count of the counter at the time of some specified event. In counter
configurations (configurations: count [0], x1 encoder [1], x2 encoder
[2], x4 encoder [4]) without store modes selected, these words are not
updated. With store modes selected, they are the stored value of the
counter at the time of the specified event (ex: rising edge of Z input).
In period/rate [5] configurations, it is the total accumulation of
unscaled Z pulses (for example, if scaling is set to 128, after 128 Z
pulses the accumulator will increase by 128 counts).
The maximum frequency that accumulation can follow in period/rate
mode is 200Hz x scalar value (ex: 200Hz x 128 is 25kHz). Finally, in
rate measurement [7] configuration, it is the total number of pulses
seen at the A input accumulated over each period as specified by the
product of the time base x gate interval. The range of values occupies
the entire 32 bit size from 0
≤ value ≤ 0xFFFFFFFF (4,294,967,295).
Changing the configuration does not clear these words.
Module/Channel Status and Programming Error Codes (Input
Words 3 and 4)
Programming Error bit (PE) - If an incomplete, incorrect or
conflicting set of configuration parameters are sent to the module, the
PE bit will be asserted and an error code will be placed in the
Programming Error Code word (assembly 68
16
). The module will not
enter a normal operational state.