206
ifm
System Manual
ecomat
mobile
SmartController (CR2500, CR2502) V05
More functions in the ecomatmobile controller
Counter functions for frequency and period measurement
10.1.5
Function PERIOD_RATIO
Contained in the library:
ifm_CRnnnn_Vxxyyzz.LIB
Available for the following devices:
•
CabinetController: CR0301, CR0302, CR0303
•
ClassicController: CR0020, CR0032, CR0505
•
ExtendedController: CR0200, CR0232
•
PCB controller: CS0015
•
SafetyController: CR7020, CR7021, CR7032, CR7200, CR7201, CR7232, CR7505, CR7506
•
SmartController: CR2500, CR2501, CR2502
•
PDM360 smart: CR1071
Function symbol:
PERIOD_RATIO
INIT
C
CHANNEL
F
PERIODS
ET
RATIO1000
Description
PERIOD_RATIO measures the frequency and the cycle period (cycle time) in [µs] during the indicated
periods at the indicated channel. In addition, the mark-to-space ratio is indicated in per mill. Maximum
input frequency
→
data sheet.
This function measures the frequency and the cycle time of the signal at the selected CHANNEL. To
calculate, all positive edges are evaluated and the average value is determined by means of the
number of indicated PERIODS. In addition, the mark-to-space ratio is indicated in [‰].
For example:
In case of a signal ratio of 25 ms high level and 75 ms low level the value RATIO1000 is
provided as 250 ‰.
In case of low frequencies there will be inaccuracies when using the function FREQUENCY. To avoid
this, the function PERIOD_RATIO can be used. The cycle time is directly indicated in [µs].
The maximum measuring range is approx. 71 min.
NOTE
For the function PERIOD_RATIO only the inputs CYL0...CYL3 can be used.
The output RATIO1000 provides the value 0 for a mark-to-space ratio of 100 % (input signal
permanently at supply voltage).
Frequencies < 0.05 Hz are no longer clearly indicated!
Summary of Contents for Ecomat 100 ecomatmobile SmartController CR2500
Page 1: ...System Manual SmartController CR2500 CR2502 CoDeSys V2 3 Target V05 7390667 00 03 2009 ...
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