Mitsubishi Electric MELSEC iQ-R Series User Manual page 242

Precautions
The following describes precautions for using the external input/output forced on/off function.
• Multiple engineering tools connected to the network can be used to register forced on/off for the same CPU module. In this
case, note the following.
• The forced on/off state registered last is handled as the on/off state of input/output devices.
• Since the on/off state displayed in engineering tools may differ from that of the CPU module, update the on/off state displayed in engineering tools.
• If a direct device is used in a program, forced on/off registration is reflected when an instruction is executed.
Ex.
When X0 is forcibly turned off
When the input device (X0) is used
 Set X0 by using the SET instruction.
 Turn on X0 because the SET instruction is being executed.
• When the external input/output forced on/off function is executed while the program of high-speed internal timer interrupt
(I48, I49) is executed, the interval of programs of high-speed internal timer interrupt is short, and a large number of forced
on/off is registered, the scan time will increase and a WDT error may occur.
• Execution of interrupt programs which are executed at a fixed scan may delay depending on the number of forced on/off
registrations and the number of refresh points of each refresh processing.
• When forced on/off is registered in the multiple CPU system configuration, registration is allowed for input/output devices
and external outputs regardless of the out-of-group I/O fetch setting
modules and the external outputs controlled by other CPU modules are not turned on or off even if forced on/off is
registered from the host CPU for the external outputs controlled by other CPU modules. Only the devices of the host CPU
module are turned on or off.
*1 For the out-of-group I/O fetch setting, refer to the following.
Page 336 Out-of-group I/O fetch setting
*2 Except when the on/off state of the input/output devices is changed by using the output instruction
• In redundant mode, when reflecting forced on/off registration information in the first scan is required, start the standby
system in the STOP state, and switch it to the RUN state after checking that the forced on/off registration information of the
control system is reflected to the standby system. When the standby system is powered on while the control system is
operating, forced on/off registration information may not be reflected in the first scan if the standby system is started with its
RUN/STOP/RESET switch set to the RUN state.
• When reflecting the external input/output forced on/off function to the standby device in a redundant system with redundant
extension base unit, perform tracking transfer for the device.
19 TEST FUNCTION
240
19.1 External Input/Output Forced On/Off Function
When the direct input device (DX0) is used
 Set X0 by using the SET instruction.
 Reflect the registered off information.
 Turn off X0 although the SET instruction is being executed.
*1
. Note, however, that the devices of other CPU
*2