MAN0964-14-EN_XL4_XL4P_UM
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CHAPTER 6: REGISTERS
6.1
Register Definitions
When programming the XL4/XL4 Prime OCS, data is stored in memory that is segmented into
different types. This memory in the controller is referred to as registers. Different groups of
registers are defined as either bits or words (16 bits). Multiple registers can usually be used to
handle larger storage requirements. For example, 16 single-bit registers can be used to store a
word, or two 16-bit registers can be used to store a 32-bit value.
Below is a list of the type of registers found in the XL4/XL4 Prime OCS.
%AI Analog Input
16-bit input registers used to gather analog input data such as voltages, temperatures, and
speed settings coming from an attached device.
%AQ Analog Output
16-bit output registers used to send analog information such a voltages, levels, or speed
settings to an attached device.
%AIG Global Analog Input
Specially defined 16-bit input registers that come from the network.
%AQG Global Analog Output
Specially defined 16-bit output registers that go to the network.
%D Display Bit
These are digital flags used to control the displaying of screens on a unit which has the ability
to display a screen. If the bit is SET, the screen is displayed.
%I Digital Input
Single-bit input registers. Typically, an external switch is connected to the registers.
%IG Global Digital Input
Specially defined single-bit inputs that come from the network.
%K Key Bit
Single-bit flags used to give the programmer direct access to any front panel keys appearing
on a unit.
%M Retentive Bit
Retentive single-bit registers.
%Q Digital Output
Single-bit output registers. Typically, these bits are connected to an actuator, indicator light,
or other physical outputs.
