HIMA HIMatrix F60 - 6.4 General Information; 6.5 Forcing - CPU OS V7 and Higher

System Manual Modular Systems 6 User Program
HI 800 191 E Rev. 2.02 Page 43 of 114
A reload may only be performed in accordance with the conditions mentioned in the previous
section. In all the other cases, stop the controller and perform a download.
TIP
Proceed as described below to be able to perform a reload even if global variable assignments
have been added:
 While creating the user program, assign unused global variables to communication
protocols.
 Assign safe value as initial value to unused global variables.
To a later time point, this assignment must only be changed and not added ensuring the
possibility to perform a reload.
6.4 General Information
Forcing is the procedure by which a variable's current value is replaced with a force value. The
current value of a variable is assigned from one of the following sources:
 a physical input
 communication
 a logic operation.
When a variable is being forced, its value is defined by the user.
Forcing is used for the following purposes:
 Testing the user program; especially under special circumstances or conditions that cannot
otherwise be tested.
 Simulating unavailable sensors in cases where the initial values are not appropriate.
WARNING
Physical injury due to forced values is possible!
 Only force values after receiving consent from the test authority responsible for the
final system acceptance test.
 Only remove existing forcing restrictions with the consent of the test authority.
When forcing values, the person in charge must take further technical and organizational
measures to ensure that the process is sufficiently monitored in terms of safety. HIMA
recommends to setting a time limit for the forcing procedure, see below.
NOTE
Use of forced values can disrupt the safety integrity!
 Forced value may lead to incorrect output values.
 Forcing prolongates the cycle time. This can cause the watchdog time to be
exceeded.
 Forcing is only permitted after receiving consent from the test authority responsible
for the final system acceptance test.
6.5 Forcing - CPU OS V7 and Higher
Forcing can operate at two levels:
 Global forcing: Global variables are forced for all applications.
 Local forcing: Values of local variables are forced for an individual user program.