Siemens 505-2557 installation and operation guide Function Enable Bits, Control Registers, Inputs

Internal Register Structures (continued)

After the values are loaded to the module, WY registers are used like those shown in Table 3-5.

Table 3-5 Function Enable Bits

WY65	Channel 1±16	Low alarm enable bits
WY66	Channel 1±16	High alarm enable bits
WY67	Channel 1±16	Scaling enable bits
WY68	Channel 1±16	Digital filtering enable bits
WY69	Channel 1±16	Averaging enable bits
WY70	Channel 1±16	Peak hold enable bits
WY71	Channel 1±16	Valley hold enable bits
WY72	Channel 1±16	Fahrenheit/Centigrade select bits
WY73	Channel 1±16	Peak hold reset bits
WY74	Channel 1±16	Valley hold reset bits
WY75	Channel 1±16	Averaging reset with new value bits
WY76±96		(Not used)

Control Registers	The control registers (X and Y discrete I/O points) are the handshake bits
	and steering logic used to load the data into the SIMATIC 505±2557 module
	and to request special operations from the module. These registers consist of
	the discrete inputs and outputs of the module.
Inputs	The SIMATIC 505±2557 input module uses a total of 5 discrete inputs in
	advanced mode. Four of the inputs are used as handshake bits from the
	module to the PLC to indicate that alarm levels, scaling data, filter and
	averaging values and function enable bits have been transferred
	successfully to the module. (See Figure 3-4).
	The remaining input bit, X16, is used by the module to inform the controller
	that the module is ready to accept data.

3-8 Advanced Function Programming SIMATIC 505±2557 Installation and Operation Guide