Fisher DPR900 User Manual page 68

5-14
Configuration
[FISHER"]
5.5.1.3 Pulse Width Modulated Output (Option 3)
This option provides for discrete output of the PID signal in a
two-stage pulse-width modulated format through DO5 This output
should be connected through an intermediate relay or contactor. If the
load is inductive, a diode must be wired across the output. An
increasing control signal forces DO5 to conduct for a longer
percentage of the specified cycle time. At the maximum output signal
(loo%), the pulse width equals the selected pulse cycle time and
results in a continuous ON signal. The cycle time must be selected in
relation to the time constant of the process and should be shorter than
five time-constants. The minimum resolution is one controller
sampling period (0.2 seconds).
Use FCODE 32 to define the total cycle time.
+
LP
A0
1-
Cycle Time Minimum Pulse 0.2s
DO5 -
v+
Pulse Length
Increasing Output Signal
DPR9Dce28
Function Parameters FCODE Range Unit Increment Default Selected
V&e Valtie
Pulse-Width Cycle time
32 l-999 s
1s
100
Output Option
When pulse-width modulated output is selected,
A01 must be shorted on the connection terminal
block (Pins 9 and 10).
5.52 Discrete Outputs
The DPRSOO Controller provides for the use of 24Vdc discrete outputs
to be used for external indication of switching. Select active state
definition for DO14 using FCODE 129 thru 132. The controller
defines a discrete output signal as active when conducting or open.
Change 7 -September 1991