AutomationDirect DL205 - Module Operation; Channel Scanning Sequence for a DL230 CPU (Multiplexing)

DL205 Analog Manual, 7th Edition Rev. D
8-7
Chapter 8: F2-02DA-1, F2-02DA-1L, 2-Channel Analog Current Output
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Module Operation
Before beginning to write the control program, it is important to take a few minutes to under-
stand how the module processes the analog signals.
Channel Scanning Sequence for a DL230 CPU (Multiplexing)
The DL230 can send one channel of data per CPU scan. The module refreshes two field
devices on each scan, but new data can only be obtained from the CPU at the rate of one
channel per scan. Since there are two channels, it can take two scans to update both channels.
However, if only one channel is being used, then that channel will be updated on every scan.
The multiplexing method can also be used for the DL240, DL250-1, and DL260 CPUs.
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Channel1
Channel2
Channel1
Channel2
Channel1
Scan N
Calculatethe data
Writedata
Read inputs
ExecuteApplicationProgram
Scan N+1
Scan N+2
Scan N+3
Scan N+4
Scan
Writeto outputs
System With
DL230 CPU