Chapter 2 Devices current value of C0 stays at the value 5. X0.1 0 1 2 3 4 5 2_ C0 (PV) (SV) 0 Y0.0,C0 2.2.12 32-bit Counters (HC) Characteristics of the 32-bit counter 32-bit general-purpose addition/subtraction counter 1. The difference between the 32-bit general-purpose addition counters and the 32-bit general-purpose subtraction counters depends on the states of the special auxiliary relays SM621–SM684. For example, the counter HC0 is an addition counter when SM621 is OFF, whereas HC0 is a subtraction counter when SM621 is ON. 2. You can use either the constant or the value in the data registers as the counter setting value, and this setting value can be positive or negative.
If you use the value in the data registers as the counter setting value, this setting value occupies two consecutive registers. 3. For the general-purpose counter, the current value of the counter is cleared when power is lost. If the counter is latching, the current value of the counter and the state of the contact before loss of power is retained. The latched counter counts from the current value when power is restored. 4. If the counter counts up from 2,147,483,647, the next incremental value is -2,147,483,648. If the counter counts down from -2,147,483,648, the next incremental value is 2,147,483,647.
2-65 0.0 Item 32-bit counter Type Up/down counter Up counter High-speed counter Number HC0–HC63 HC64–HC199 HC200–HC255 Direction Counts up/down Counts up Counts up/down Setting value -2,147,483,648 to +2,147,483,647 Specification of the counter setting value The counter setting value can be either the constant or the value occupying two data registers (32-bit). Change of the current value The counter keeps counting even after the value of the counter matches the counter setting value. Output contact The contact is ON when the value of the addition counter matches the counter setting value.
The contact is reset to OFF when the value of the subtraction counter matches the counter setting value. Reset When the RST instruction is executed, the current value is cleared to zero, and the contact is reset to OFF. Action of the contact After the DCNT instruction scan is complete, the contact acts.