Virtual logic gates (xVyyy)
This article will guide you in setting up virtual logic gates (VLG), in order to implement conditional functions. VLGs can be cascaded and nested. The result of these logic functions can dictate automatic actions to be performed by the Davicom upon very specific events, or can be used to qualify other inputs. VLGs can also be used to display a specific result on a DavLink I/O Indicator (refer to Section 11.3.2.7 on page 225 of the Reference Manual) or beside an I/O State LED (refer to Section 11.3.2.8 on page 228 of the Reference Manual). Each virtual logic gate is set individually according to its use and function.
VLGs allow you to program Davicom units so they act intelligently. For example, if you do not want the Davicom to call many times during the night for alarms all related to a main power failure, you can program the unit to only react to the root cause of the problems.
To configure virtual logic gates, click the Unit Configuration icon (
) then on the Inputs tab and select Virtual Logic Gates.
Example from image above: VLG 1V06 verifies if at least one operand calls for a generator test. 1H001 is a timer that has been set to automatically perform the generator test monthly. 1O003 is a virtual relay acting as a remote switch to manually trigger a generator test in addition to those normally activated by the timer. This setting allows you to manually Force-On/Off the virtual relay in order to start/end the test without affecting the periodic automatic test settings.
The upper portion of the VLG configuration dialog box allows you to set the following parameters:
VLG Number: Select from the dropdown list the number of the specific VLG you wish to configure. VLGs are all identified by the V letter, followed by one, two or three digits (up to 128 depending on your Davicom model).
Note: The identifier for VLGs will begin by a digit (1 to 4) to identify a specific Davicom unit when several DV-208/216 units are networked together (SuperMAC). Otherwise it must begin with the digit 1.
Enable: Check this box to enable the VLG and its automatic actions. Default setting is enabled. You can also enable/disable VLGs by using the Enable and Disable buttons on the DavLink Command Bar (refer to Section 16.1.4 on page 279 of the Reference Manual).
Default Description when Active: Long Unicode description used to describe the VLG when the result is logically True. (Maximum 30 alphanumerical Unicode characters). Refer to this article for more details.
Alternate Description when Active: Short ASCII description used to describe the VLG when the result is logical True. (Maximum 18 alphanumerical ASCII characters).
Default Description when Normal: Long Unicode description used to describe the VLG when the result is logical False. (Maximum 30 alphanumerical Unicode characters).
Alternate Description when Normal: Short ASCII description used to describe the VLG when the result is logical False. (Maximum 18 alphanumerical ASCII characters).
The lower portion of the Virtual Logic Gates configuration dialog screen is divided into three tabs. To configure Vocal Descriptions, refer to this article. To configure automatic Actions, set the following parameters:
Action Type: Select from the dropdown list the action (MIN, MAJ, CMD or QLF) that will automatically be performed by the Davicom unit when the resulting value of the logic gate on all operands toggles from a logical 0 (False) to a logical 1 (True). Default action is CMD. Refer to this article for more details.
Alarm-Call List: If you selected MIN or MAJ for Action Type, you need to select a specific Alarm-Call List from the dropdown list (1 to 8). Default value is 1. Refer to this article for more details on alarm-call lists.
Logic Gate: Select one of the 4 Logic Gates (AND, OR, NAND, NOR) to be applied to all input operands in order to produce the resulting logic value for the VLG.
Note: Select the appropriate gate so that it produces a logical 1 (True) when you want the automatic Action to be performed. Note that each operand can be inverted.
Operands: Up to 5 Operands of any type (input, output, timer, flag, etc.) can be defined as inputs for the Logic Gate. Any Operand can be inverted by adding the exclamation sign “!” before its identifier (!1S01 for example).
Note: If you have more than 5 Operands, you can cascade several VLGs. When less than 5 Operands are used, empty or disabled Operands are considered a logical 1 (True) for AND or NAND Logic Gates, and at logical 0 (False) for OR or NOR Logic Gates.
Controlled Relays: The Davicom can act automatically on up to 6 different relays (physical or virtual) when the resulting value of the logic gate on all operands toggles from a logical 0 (False) to a logical 1 (True). Use the xRyy identifier for physical relays and xOyyy for virtual relays. By default, relays will react in the Follow operating mode if you do not add any letter to the relay identifier. For the Latch mode, you must add the letter L to the relay identifier. For the Davicom to pulse a relay, you must add the letter P to its identifier. For the Davicom to release a relay, you must add the letter R to its identifier (1R04R for example).
Note: You must make sure each relay is configured for the operating mode you wish to use. You cannot Latch a relay that is configured Pulse Only for example. Refer to this article for more details on relay configuration.
Alarm Signalling On: If you selected the MIN or MAJ Action Type, you need to check this box for the Davicom to initiate the appropriate Alarm-Call Sequence (ACS) when the resulting value of the logic gate on all operands toggles from a logical 0 (False) to a logical 1 (True). If you do not check this box, no ACS will be initiated, but the Davicom will still log alarms (MAJ and MIN) and commands (CMD), and act on relays. By default this box is checked. Refer to this article for more information on ACS.
Return to Normal Signalling On: If you selected the MIN or MAJ Action Type, you need to check this box if you want the Davicom to initiate the appropriate ACS to report a Return to Normal when the resulting value of the logic gate on all operands toggles from a logical 1 (True) to a logical 0 (False). If you do not check this box, no ACS will be initiated, but the Davicom will still log the Return to Normal (for MAJ, MIN and CMD) and act on relays. By default this box is checked.
Delay Before Action: To avoid untimely automatic Actions caused by short-duration false alarms, a delay can be programmed before the Davicom responds to the result of the VLG. This sets the minimum duration that a logical 1 (True) result must be in effect before the Davicom considers that it is a valid condition and executes the programmed automatic Actions. Default setting is 0 (no delay). You can select a value between 0 and 9999 seconds using the arrows or by typing in the number.
Delay Before Return to Normal: To avoid untimely automatic actions caused by short-duration Return to Normal conditions, a delay can be programmed before the Davicom responds to the Return to Normal condition. This sets the minimum duration that the Return to Normal condition must be in effect before the Davicom considers it to be a valid condition, and thus execute the programmed Return to Normal actions. Default setting is 0 (no delay). You can select a value between 0 and 9999 seconds using the arrows or by typing in the number.
Custom Log: Davicom units can provide one custom log in addition to the extensive system log. This allows Davicom users to focus-in on desired information. Check this box if you want to record events related to the selected VLG in the custom log. By default this box is not checked. This setting also enables periodic data logging (refer to Section 4.7.3.1 on page 138 of the Reference Manual for more details).
