Omron PRT1-COM Operation Manual page 152

Counter Units
Reset mode Input
1 Encoder input Z
2 External input
3 Encoder input Z +
external input
4 Internal Reset Bit
5 Encoder input Z +
internal Reset Bit
6 External output +
internal Reset Bit
7 Encoder input Z +
external input + internal
Reset Bit
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The possible combinations (reset modes) are shown in the following table.
Encoder input Z
Reset
External input
Reset
Encoder input Z
External input
Reset
Internal Reset Bit
Reset
Encoder input Z
Internal Reset Bit
Reset
External output
Internal Reset Bit
Reset
Encoder input Z
External input
Internal Reset Bit
Reset
Note 1. Setting of the reset mode is performed in bits 12 to 14 in word n+2 of the
output area.
2. The Counter Unit will execute reset with the first count following the
fulfillment of the reset conditions.
3. Encoder input Z is only effective for the rising edge. When using the encoder
input Z under AND conditions with other inputs, ensure that encoder input Z
will turn ON last.
4. When repeating reset for the count value, allow an interval of at least 0.1 ms
before switching ON the encoder input Z and at least 1 ms before switching
ON the external inputs.
5. It is not possible to execute ON/OFF timing for the internal Reset Bit with
perfect accuracy, due to the communications time required for remote I/O
communications.
Count Value Setting
The count value (the present value) for the Counter Unit can be set as required,
to any value in range --8,388,608 to +8,388,607. Count value setting can be
performed in BCD or hexadecimal.
Note 1. Count value setting is performed by setting a value in words n, n+1 of the
output area as shown below, and switching ON the Count Value Setting Bit
(word n+2, bit 02).
2. Specify whether the setting will be made in BCD or in hexadecimal in the
Data Code Switching Bit (word n+2, bit 03).
Counter reset condition and timing
Section 7-3