Campbell CR800 Specifikace stáhnout pdf (Strana 175)

Section 7. Measurement Instructions

counted if centered around +2.5 V with deviations ≥ ± 2.5 V for ≥ 1.2

microseconds.

Low Level AC (Pulse Channels Only)

Input Hysteresis: 15 mV

Maximum Input Voltage: 20 V peak-to-peak

Input Voltage and Frequency Range

(16 bit counter required above 2.56 kHz)

20 mV 1.0 Hz to 20 Hz

200 mV 0.5 Hz to 200 Hz

2000 mV 0.3 Hz to 10,000 Hz

5000 mV 0.3 Hz to 20,000 Hz

Switch Closure

• Pulse Channels

A switch closure is connected between P1..P2 and analog ground.

When the switch is open, the CR800 pulls the pulse channel to 5 V

through a 100 kOhm impedance. When the switch is closed, the

pulse channel is pulled to ground. The count is incremented when

the switch opens.

Minimum Switch Closed Time: 5 ms

Minimum Switch Open Time: 6 ms

Maximum Bounce Time: 1 ms open without being counted

PulseCountReset

PulseCountReset is used to reset the pulse counters and the running averages

used in the pulse count instruction. The 16 bit counters can count up to

decimal 65535. More counts than 65535 result in an over-range condition.

With each scan, the CR800 reads the counts accumulated since the last scan

and then resets the counter. If the scans stop, as in a program with more that

one Scan loop, the counter continues to accumulate counts until another scan is

initiated or it over-ranges. If the running averaging is in use, the over-range

value will be included in the average until for the duration of the averaging

period (e.g., with a 1000 millisecond running average, the over-range will be

the value from the PulseCount instruction until 1 second has passed.

Resetting the average prior to (re)starting the scan avoids this.

PulsePort (Port, Delay)

This instruction toggles the state of a port, delays the specified amount of time,

toggles the port, and then delays a second time. The second delay in the

instruction allows it to be used to create a 50 percent duty cycle clock. The

instruction has the following parameters:

Parameter

& Data Type

Enter

Port

Constant

The control port that should be set by the instruction. The number of the

port (1-8) is entered:

Delay

Array

The amount of time, in microseconds, that the instruction should delay after

each toggle of the port

7-21

1 2 ... 170 171 172 173 174 175 176 177 178 179 180 ... 323 324

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Campbell CR800 Specifikace Strana 175

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