GE GFK-0804B Special Coils, Sec Clock C1018, Start-up Scan Coil C1019, Hold Output Coil C1021

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Special Coils

The Micro PLC provides three special-purpose coils:

H0.1 sec clock

Hstart±up scan coil

Hhold output coil

0.1 Sec Clock (C1018)

Coil C1018 is a pulse generator. The pulse width is shown below. This coil is a read-only coil. It can only be used as a program input, not as an output.

Pulse signal

50msec

0.1 sec

This coil should be used as a one-shot contact that feeds a regular coil.

Start-up Scan Coil (C1019)

46103

When the controller starts operating, this coil goes ON for one scan. It is a read-only coil. It can only be used as a program input, not an output.

46104

Run/power on

Stop/power off

1 Scan

Hold Output Coil (C1021)

This coil can be used to control the state of the program outputs when the PLC is put in stop mode. As a group, all of the outputs can either hold their last state, or be set to OFF.

If all outputs should hold their last state, set coil C1021 to ON (1).

If all outputs should be set to OFF, set coil C1021 to OFF (0).

Note: This function takes precedence over the Clear Data function of the programming software (key F7 in the Online menu).

GFK-0804B Chapter 1 Programming for the Micro PLC 1-7