Definition of the Custom Logic Variables

Introduction

The custom logic editor enables you to implement commands in the control program which directs the LTMT main unit:

• To read or write to temporary registers

• To read or write to non-volatile registers

• To read or write to LTMT main unit registers, refer to Definition of LTMT Main Unit Variables.

The LTMT main unit defines each custom logic register by an integer describing its address in custom logic memory space. The value of this integer begins at address 0 and the maximum address is equal to 1 less than the number of memory locations available for registers in the LTMT main unit.

Temporary Registers

The LTMT main unit provides registers in temporary memory that can be accessed by logic commands. Because these registers exist in temporary or volatile memory, they do not retain their value settings when power to the controller is cycled.

300 temporary registers are available, at addresses ranging from 0 to 299.

The number of temporary registers available can be read in the LTMT main unit register at address 1204 (0x04B4), custom logic temporary space.

Non-Volatile Registers

The LTMT main unit provides registers in non-volatile memory for use by logic commands. Because these registers exist in non-volatile memory, they retain their value settings when power to the controller is cycled.

64 non-volatile registers are available, at addresses ranging from 0 to 63.

The number of non-volatile registers available can be read in the LTMT main unit register at address 1205 (0x04B5), custom logic non-volatile space.