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

DL205 Analog Manual, 7th Edition Rev. D
11-8
Chapter 11: F2-08DA-2, 8-Channel Analog Voltage Output
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Module Operation
Before beginning to write the control program, it is important to take a few minutes to
understand how the module processes the analog signals.
Channel Update Sequence for a DL230 CPU (Multiplexing)
If a multiplexing program is being used, only one channel of data can be sent to the output
module on each scan. The module refreshes both field devices on each scan, but only new
data can be read by the CPU at the rate of one channel per scan. Since there are eight
channels, it can take eight scans to update all channels. However, if only one channel is
being used, 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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Channel 1
Channel 2
Channel 3
Channel 4
Channel 8
Scan N
Calculatethe data
Writedata
Read inputs
ExecuteApplic ationProgram
Scan N+1
Scan N+2
Scan N+3
Scan N+8
Scan
Writeto outputs
System Using
Multiplex
Method
(DL230)
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