Analog Device Ethernet Remote I/O Forcing Mode
Original instructions
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Introduction
Input and output values of Modicon X80 analog modules can be forced through the device DDT value.
NOTE: Modicon X80 discrete modules values are forced using the EBOOL mechanism, refer to chapter Force Mode. This does not apply to BMEAH•0•12 modules.
Forcing input and output values in a running controller can have serious consequences to the operation of a machine or process. Only those who understand the implications in the controlling logic, and who understand the consequences of forced I/O on the machine or process, should attempt to use this function.
WARNING
UNINTENDED EQUIPMENT OPERATION
You must have prior knowledge of the process, the controlled equipment and the modified behavior in Control Expert before attempting to force analog inputs or outputs.
Failure to follow these instructions can result in death, serious injury, or equipment damage.
Modicon X80 Analog Device T_U_ANA_VALUE_•• Structure
The following table shows the content of analog devices DDT type used to force a value:
Standard Symbol
Type
Meaning
VALUE
INT
Channel value. It represents the value used in the application and is either the FORCED_VALUE or the TRUE_VALUE depending on the FORCED_STATE.
FORCED_VALUE
INT
Value applied to an output or interpreted as an input during forcing. If FORCED_STATE = 1 then VALUE = FORCED_VALUE
FORCE_CMD
BOOL
Parameter used to force or unforce an analog output or input value
FORCED_STATE
BOOL
Forcing status:
  • 0: value is not forced
  • 1: value is forced
TRUE_VALUE
INT
Represents the true value of the analog output or input whatever the state of the forcing command
Forcing a Value with the Animation Tables
To force a DDT value in an animation table proceed as follows:
Step
Action
1
Select the chosen analog channel.
2
Set the FORCED_VALUE parameter value of the selected channel to the chosen value, for details on how to set a value, refer to chapter Modification Mode.
3
Set the FORCE_CMD parameter to 1.
4
Result:
  • Check that forcing is applied: FORCED_STATE needs to be equal to 1
  • VALUE = FORCED_VALUE
Unforcing a Value with the Animation Tables
To unforce a DDT value in an animation table proceed as follows:
Step
Action
1
Select the chosen analog channel.
2
Set the FORCE_CMD parameter to 0.
3
Result:
  • Check that forcing is released: FORCED_STATE needs to be equal to 0
  • VALUE = TRUE_VALUE