EUCHNER CIS3(A) - Manual (Page 5)

EUCHNER Identsystem CIS3
071652-01-8/99 Subject to technical modifications page 5 / 23
3. Pulse Timing Diagram for the Read-Only Head CIT3PL...
The above pulse timing diagram shows the time response of the input and output signals of
the read-only head with respect to the PLC.
As soon as a data carrier is read in, the first digit is disposed at the data outputs of the read-
only head. To switch the following digits to the data outputs, you have to give a HIGH-pulse
to the Skip-input.
With every HIGH-pulse to the Skip-input, the digits are switched on.
The read-only head stores the coded information read from one data carrier until another
data carrier has been read.
The storage function offers the following advantage:
At high relative speeds between Read head and data carrier, the dwell time of a data carrier
in the read-only head’s response range may, under certain circumstances, be shorter than
the scan time of the PLC control. Owing to the storage characteristics of the Read head, the
code can nevertheless be read by the PLC in the next scan time cycle.
The additional STROBE output, when at HIGH level, indicates that a data carrier is located in
the read head’s response range.
This output is set to HIGH as soon as the Read head has been able to read 4 decimal digits.
If more than 4 digits are required, it is not possible to check with the STROBE output
whether all required digits have been read in.
If any error should occur during reading, an error message F
hex
is given at the point in the
data string. All preceding data is valid.