Channel Scanning Sequence - Automation Direct DL405 User Manual

Before you begin writing the control program, it is important to take a few minutes to
understand how the module processes and represents the analog signals.
Channel The F4–08DA–2 module allows you to update the channels in any order. Your
control program determines which channels get updated on any given scan. A
Scanning
Sequence typical ladder program will update one channel per CPU scan. So, all eight
channels can be updated every eight scans. With a D4–440 or D4–450 CPU, you
can use Immediate instructions to update all eight channels in the same scan (we'll
show you how to do this later).
F4–08DA–2 8-Ch. Analog Voltage Output
Scan
Read inputs
Execute Application Program
Calculate the data
Write data
Write to outputs
Scan N
Channel 1
Scan N+1
Channel 2
Scan N+2
Channel 3
Scan N+3
Channel 4
Scan N+4 Channel 5
Scan N+5
Channel 6
Scan N+6
Channel 7
Scan N+7
Channel 8
Scan N+8
Channel 1
19–7