214 Rockwell Automation Publication 520-UM001K-EN-E - August 2021
Appendix D Velocity StepLogic, Basic Logic and Timer/Counter Functions
- t076 [Relay Out1 Sel] = 25 “Timer Out”
- t077 [Relay Out1 Level] = 20.0 seconds
- A411 [Preset Freq 1] = 30.0 Hz
• The control terminal block is wired such that a start command will also
trigger the timer start.
• The relay output is wired to I/O Terminal 02 (DigIn TermBlk 02) so that it
forces the input on when the timer starts.
• After the timer is complete, the output is turned off releasing the preset
speed command. The drive defaults to following the analog input
reference as programmed.
Note that a “Reset Timer” input is not required for this example since the
“Timer Start” input both clears and starts the timer.
Counter Function Digital inputs and outputs control the counter function and are configured
with parameters t062...t063, t065...t068 [DigIn TermBlk xx] set to 20 “Counter
In” and 22 “Reset Countr”.
Digital outputs (relay and opto type) define a preset level and indicate when
the level is reached. Level parameters t077 [Relay Out1 Level], t082[Relay Out2
Level], t070 [Opto Out1 Level] and t073 [Opto Out2 Level] are used to set the
desired count value.
Parameters t076 [Relay Out1 Sel], t081 [Relay Out2 Sel], t069 [Opto Out1 Sel]
and t072 [Opto Out2 Sel] are set to 26 “Counter Out” which causes the output to
change state when the level is reached.
Example
• A photo eye is used to count packages on a conveyor line.
• An accumulator holds the packages until 5 are collected.
• A diverter arm redirects the group of five packages to a bundling area.
• The diverter arm returns to its original position and triggers a limit
switch that resets the counter.
• Parameters are set to the following options:
- t065 [DigIn TermBlk 05] = 20 “Counter In”
- t066 [DigIn TermBlk 06] = 22 “Reset Countr”
- t076 [Relay Out1 Sel] = 26 “Counter Out”
- t077 [Relay Out1 Level] = 5.0 Counts
DigIn TermBlk 06
Reset Counter
Limit Switch
DigIn TermBlk 05
Counter In
Photo Eye
Start
Output
Frequency
Relay Out
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