36
•
750-404/000-003 [Frequency Counter 0.1 Hz-100 kHz]
Functional
Description
WAGO-I/O-SYSTEM
750
I/O
Modules
Approvals (cf. Chapter 2.2 of the Coupler/Controller Manual)
C
UL
US
(UL508)
C
UL
US
(UL1604)
Class I Div2 ABCD T4A
DNV (Det Norske Veritas)
Cl. B
KEMA
II 3 G EEx nA II T4
Conformity Marking
More Information
Detailed references to the approvals are listed in the document "Overview
Approvals WAGO-I/O-SYSTEM 750", which You can find on the CD ROM
ELECTRONICC Tools and Docs (Item-No.: 0888-0412-0001-0101) or in the
Internet under:
Service
Downloads
Documentation
WAGO-I/O-SYSTEM 750
System Description.
2.1.4.6 Functional Description
The counter module acquires the time between one or more rising edges of the
CLOCK input signal and calculates the frequency of the applied signal.
The calculation and process image update are initiated every 1
st
, every 4
th
or
every 16
th
rising edge depending on the integration time selected via the
CONTROL byte. The first detection of a rising edge starts the cyclic period
measurement and cannot provide a valid frequency value. In this case the
module will send 0xFFFFFFFF
H
for input information. The same input value
is returned when a static high or static low signal is applied to the CLOCK
input.
If there are no signal changes seen at the CLOCK input, the module can be
forced to update the process image after defined parameterizable time spans
(Watchdog time). In this state the module will send the non valid value
0xFFFFFFFF
H
too.
The following figures illustrate a process data cycle.
