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The SYS 600 provides a wide range of blocking attributes, which are included in the Blocking Display. To provide a blocking handling mechanism in a more clear and rational way, the following blocking types are provided by the Blocking Display: • Alarm blocking: alarms are not raised, regardless of the object state.

• Update blocking: indications are not updated by the process. • Control blocking: operation commands are not sent to the process.

• Event blocking: event registrations are not made, events are not shown in the Event Display.

• Printout blocking: events are not sent to the printer. • Action blocking: event channel activation is blocked.

Fig. 7.2.1.-1 shows the settings of Blocking Display as an example.

As stated before, simply setting the corresponding blocking attribute value to 0 or 1 performs the blocking and deblocking of a signal. This, and the fact that there is no tag in the database indicating when an individual signal has been blocked or

deblocked, means that the Blocking Display cannot be a dynamic display. Polling the blocking attributes of all the signals in the database at regular intervals would be a too heavy load for the system. A Refresh function is provided to enable updating of the blocking information.

Finally, the blocking activity must be expanded to the signal level. The reason for this is that, for example, in case of an oscillating signal, you must be able to block it but leave the other signals (related to the device in question) unblocked to minimize the information loss. Blocking is possible either by setting the blocking state of each signal presented on the list or fetching any signal from the database and set its blocking.

When a signal is update-deblocked, its state in the database is not necessarily up to date, since the state of the process device may have changed while the signal has been update-blocked. Therefore, the state of each signal must be updated from the process when the signal is update-deblocked.

The blocking Display is refreshed by selecting Blocking Display > Refresh or by clicking the appropriate toolbar button.

7.3.1.

Setting signal blocking state

The blocking state of the signal can set by clicking the selection box of the signal in question. If there is a cross in a selection box, the signal in question will be blocked. Otherwise the signal will not be blocked. Since a signal can be either of indication or control type, the selection boxes corresponding to either one of the blocking types is unset and unavailable, depending on the signal.

Alternative way to set the blocking states of the signal is to use the copy-paste function. The selected signal's blocking states are copied by pressing CTRL-C and the blocking states can be set to another signal by pressing CTRL-V.

Note that if all the blockings are deblocked, the signal will be removed from the Blocking Display. If a non-internal signal is in the update-deblocked mode and it is connected to a process, its state will be updated. See also Section 7.3.2. Predefined blocking conditions concerning the blocking conditions.

7.3.2.

Blocking attributes and blocking types

The SYS 600 provides a wide range of blocking attributes, which are included in the Blocking Display. To provide a blocking handling mechanism in a more clear and rational way, the following blocking types are provided by the Blocking Display:

• Alarm blocking (AB): alarms are not raised, regardless of the object state. • Update blocking (UB): indications are not updated by the process.

• Control blocking (UB): operation commands are not sent to the process. • Event blocking (HB): event registrations are not made, events are not shown in

the Event Display.

• Printout blocking (PB): events are not sent to the printer. • Action blocking (XB): event channel activation is blocked.

133 It must be noted that the abbreviations on the list above are process object attributes, but abbreviations used in the Blocking Display. To clarify the connection between the blocking types and the attribute values, they are given together in the Table 7.3.2-1.

Table 7.3.2-1Blocking types and their attribute values Blocking type Abbreviation in Blocking Display Attribute values

Alarm blocked AB AB = 1 Update blocked UB UB = 1 Control blocked CB UB = 1 Event blocked EB HB = 1 Printout blocked PB PB = 1 Action blocked XB XB = 1

Predefined blocking conditions

An alarm blocking can be made only if an alarm class has been predefined for it. The values of the process object attributes are to be checked to decide whether it is reasonable to make a blocking for it or not.

The following conditions apply for blockings. These conditions have been predefined for blockings in order to prevent unnecessary operations. Table 7.3.2-2 Conditions that apply for blockings

Blocking type Condition

Alarm blocking Alarm blocking is possible when AC > 0

Printout blocking Printout can be blocked (a printer has been defined) when LD > 0

Action blocking Action blocking is possible when AE = 1 Event blocking Event blocking is possible when HE = 1

Update blocking Update blocking is always possible for an input object Control blocking Control blocking is always possible for an output object

7.3.3.

Locating an object

Right-click on a selected event line to open a shortcut menu. In this menu, you can select Locate object in DMS or Locate object in Monitor Pro. For more

information about locating an object, refer to Section 5.3.5. Locating object.

7.3.4.

Copying blockings

You can copy selected blockings from the lists and copy them to Windows' clipboard as text format. Columns are separated with tabulator.