Specifications

Writing Your Control Program
The mnemonic for the counter instruction is UDC (up-down counter).The DL06 can have
up to 128 counters, labeled CT0 through CT177. The high speed counter in the HSIO
circuit is accessed in ladder logic by using UDC CT174 and CT176. It uses counter registers
CT174 through CT177 exclusively when the HSIO mode 10 is active (otherwise, CT174
through CT177 are available for standard counter use). The HSIO counter needs two
registers because it is a double-word counter. It has three inputs as shown. The first input
(Enable) allows counting when active. The middle input is used to preload the counter value.
The bottom signal is the reset. The Preload Input must be off while the counter is counting.
The next figure shows how the HSIO counter will appear in a ladder program. Note that the
Enable Interrupt (ENI) command must execute before the counter value reaches the first
preset value. We do this at powerup by using the first scan relay. When using the counter but
not the presets and interrupt, we can omit the ENI.
When the enable input is energized, the up/down counter CT174 will respond to pulses on
X0 and increment. The up/down counter CT176 will respond to pulses on X1 and
increment. The reset input contact behaves in a logical OR fashion with the physical reset
input. X2 (when selected) resets counter 1. X3 (when selected) resets counter 2. So, the high
speed counter can receive a reset from either the contact(s) on the reset rung in the ladder,
OR the external reset X2 or X3, if you have configured X2 or X3 as an external reset.
DL06 Micro PLC User Manual, 3rd Edition, Rev. C
E–15
Appendix E: High-speed Input and Pulse Output Features
1
2
3
4
E
6
7
8
9
10
11
12
13
14
A
B
C
D
Direct SOFT 5
Required
Preset Range:
1-99999999
Reset Input
UDC
CT174
Kxxxxxxxx
Enable Input
Preload Input
ENI
SP1
XX
XX
XX
(or CT176)
Reset Input
UDC
CT174
Kxxxxxxxx
Enable Input
Preload Input
Reset Input
UDC
CTxx
Kxxxxxxxx
UP Count
DOWN Count
Standard Counter Function HSIO Counter Function
Counts UP and DOWN Counts UP only
Reset input is internal only Reset may be internal or external
Preload counter by write to value Can use Preload Input to change count
(or CT176)