Rockwell Automation 1769-OF4 Compact Analog Output Module - Manual (Page 31)

Publication 1769-UM020A-EN-P - December 2009 31
Module Data, Status, and Channel Configuration Chapter 3
Input Data File The input data file lets you access analog module read data for use in
the control program, via word and bit access. The data table structure
is shown in the table below. For each output module, slot
x, word 0
contains the output-channel status bits. Words 1…4 in the intput data
file contain the output channel data echo values. The most significant
bit (MSB) is the sign bit, which is in two’s complement format. ‘Nu’
indicates not used with the bit set to zero.
General Status Bits (S0…S3)
Word 0, bits 0…3 contain the general operational status bits for output
channels 0…3. When set (1), these bits indicate an output-clamp
range error associated with that channel. The over- and under-range
bits are logically ORed to the appropriate general status bit.
Over-range (high clamp) Status Bits (O0…O3)
Over-range (high clamp) status bits for output channels 0…3 are
contained in Word 0, bits 8, 10, 12, and 14. When set (1), these bits
indicate an output value sent to the module is greater than or equal to
the user-configured high clamp value for the output channel. The
module clamps the analog output signal at the high clamp value.
These bits are automatically reset (0) by the module when the high
clamp condition clears, unless the channel’s clamp status bits are
latched. The module’s output signals always return to normal
operation when directed to values allowed by the high clamp and low
clamp settings. If the channel’s clamp status bits are latched, a set (1)
high clamp status bit clears via the corresponding Cancel High Clamp
Latch bit in your output data file.
Input Data Array
Word/Bit 15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00
Word 0 U3 O3 U2 O2 U1 O1 U0 O0 NU NU NU NU S3 S2 S1 S0
Word 1 SGN Output Data Loopback/Echo Channel 0
Word 2 SGN Output Data Loopback/Echo Channel 1
Word 3 SGN Output Data Loopback/Echo Channel 2
Word 4 SGN Output Data Loopback/Echo Channel 3