Writing The Control Program; Update Any Channel; Calculating The Digital Value - Automation Direct DL405 User Manual

Writing the Control Program

Update Any As mentioned earlier, you can update two channels per scan using regular I/O
Channel instructions, or any number of channels per scan using immediate I/O instructions.
The following diagram shows the data locations for an example system. You use
the channel select outputs to determine which channels get updated (more on this
later).
Calculating the Your program has to calculate the digital
Digital Value value to send to the analog module.
There are many ways to do this, but most
applications are understood more easily
if you use measurements in engineering
units. This is accomplished by using the
conversion formula shown.
You may have to make adjustments to
the formula depending on the scale you
choose for the engineering units.
V40502
MSB
Data Bits
Channel
Select Bits
Output
Enable Bit
Channels 9 – 16
F4–16DA–1 16-Ch. Analog Current Output
F4–16DA–1
8pt 8pt 32 16pt 16pt
Output Output Output Output Input
Y0 Y10 Y20 Y60
– – – –
Y7 Y17 Y57 Y77
V40500 V40503
LSB MSB
Channel
Select Bits
Output
Enable Bit
Channels 1 – 8
A + U 4095
H * L
A = Analog value (0 – 4095)
U = Engineering Units
H = high limit of the engineering
unit range
L = low limit of the engineering
unit range
16–11
16pt
Input
V40501
LSB
Data Bits