Hardware reference guide

Intelligent/Special Purpose
358
35013379 02 October 2007
COUNT DOWN
Example
The COUNT DOWN example uses the same wiring as in the count up example,
except the Input 1B+ level is changed to common (connected to Vref-) for Pulse
Inputs illustrated in Wiring Diagrams 1 and 2. For Quadrature Inputs, no wiring
change is required as the count direction is decoded internally by sensing the phase
shift change between inputs A and B.
The User Logic is the same as for the count example. The actual operation of the
module is different in that the output associated with maximum count turns on after
zero count has been reached.
The example configures the module to decrement the input count from the maximum
value, turn on an output at a setpoint value of 50, and turn on a second output after
the input counter had reached zero and rolled over to the maximum count; the
operation is then repeated. The initial loading of the maximum count will not cause
its associated output to turn on.
RATE SAMPLE
Example for
Either Pulse or
Quadrature Input
Field connections for this example are illustrated in Wiring Diagrams1–4. The
connections on terminals 15 and 16 are optional, depending on the use
requirements of the outputs. Terminals 39 and 40 always require the 24 Vdc supply
connections. The maximum allowable Vref value is 30 Vdc. Input pulse on-off
threshold levels for the 5 ... 24 Vdc Vref range are listed in the module specification
table. The minimum differential input is 1.8 V.
As with count examples, tables are set up and transferred to the module using block
moves. The User Logic for Rate Sample is the same as that used for Pulse Input
Count Up/Down.
Module
Configuration
The following table shows the module configurations.
400101 0140 CONFIGURE command, Disable Counter 2
400102 1000 Pulse input, Rate Sample ON, disable outputs at bus communication
loss (Note: Bits 11 and 12 were not required.)
400103 0000
Not used by this command
400104 0000
400105 0000
400106 0000
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