The Basic I/O 1
DIGITAL INPUTS:
Digital input modules detect the presence or absence of a field signal. Module types vary from AC to dry contact sense. Because the industry standard modules are optically isolated, the response time performance of digital input instructions can be limited by the delay in the input modules themselves. Some modules can have rise and fall times of up to 40 milliseconds.
Digital input instruction types are: |
|
Read | Read the On or Off state of all inputs. This data is |
| updated every 10 Milliseconds. |
Edge Detection | |
| within 1 millisecond of their occurrence. Action is |
| only reported every 10 milliseconds. |
Pulse Widths | BASIC I/Os can report pulse width measurements |
| from .01 seconds to 46.6 hours. Minimum resolution |
| is .01 seconds (Pulse widths up to 10.9 minutes). |
| Either on or off pulses can be measured. |
Pulse Counting | Pulses can be counted up to a total of 65,535. To be |
| reliably counted, pulses must have a minimum On and |
| Off time of 1 millisecond. Thus the maximum |
| counting rate for a 50% duty cycle square wave is |
| once every 2 milliseconds (500Hz). |
Frequency | Direct frequency measurements can be made on |
| digital inputs at rates of up to 500 Hz with a user |
| specified time base of from .01 to 2.55 seconds. |
