Input / Output Register - Hitachi EH-150 Series Applications Manual

Chapter 5 Control of EH-SIO
5.2

Input / Output register

By using an input / output register, the state of EH-SIO can be checked or EH-SIO can be reset* without using TRNS
9 command.
The input / output register is assigned to the I/O area (area of 4W/4W) of EH-SIO. The input register is in
WXus0-WXus3, and especially WXus0 and 1 are called status register. The output register is in WYus4-WYus7, and
especially WYus4 and 5 are called control register. The status register indicates the state of EH-SIO. The control
register is used when sending instructions from CPU module to EH-SIO.
* It restricts, when the system of EH-SIO is operating normally. Reset by the hard switch is required at the time of serious failure
occurred.
« Note »
Be careful of the treatment of the input / output register by the user program, or a set / reset.
 If the value of an input-and-output register is rewritten during TRNS 9 command execution, the status
of the handshake of CPU module and EH-SIO may shift. The handshake once shifted does not return to
normal, unless it carries out the initial of the TRNS 9 command.
 If initial setting is completed by EH-SIO at the time of Modbus slave mode, Hi-Protocol mode, and
simple data link mode operation, a handshake will be started automatically (TRNS9 command is not
executed.). If the value of an input-and-output register is rewritten during each mode operation, EH-SIO
may stop operating. In this case, reset and initial setting of EH-SIO are needed.
Reference :
Exchanging data between CPU module and EH-SIO is automatically executed by TRNS 9 command. It is not always
necessary to use input / output register for programming, except for controlling hand shake signals.
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