This is a brief overview of offline validation in PMT hardware
Explanation of offline validation:
Offline validation on terminals/door controllers is tag validation by the terminal/door controller itself, when the connection to the system controller has been lost. In a normal environment, access decisions are made by the system controller. When the system controller goes offline, offline validation allows the door controllers to make limited access decisions as a fall-back form of validation. A door controller is considered offline when it has lost connection to its parent system controller.
This is important as it has the ability to keep a door/reader working when RS485/LAN connection to the system controller is interrupted. It is a limited form of validation in that only a certain amount of decisions can be made, and is limited to a certain amount of tags.
Units that currently support offline validation:
- DC (Cluster controller in DC mode)
- iTT
- iTRT
- BMTA
Offline validation is enabled by default for any of the above units when installed in an Impro system (IXP220, IXP400i, Access Portal). Offline validation can be disabled in software, if required, forcing all door controllers to use system controller validation only. If disabled, door controllers will be unresponsive should the system controller go offline.
Functions not supported in offline validation:
- APB rules (APB is controlled by the system controller)
- Cross-controller rules (common zones, interleading zones, nested zones)
- Zone counting
- Inhibit scanner (across door controllers)
- Cross-device actions
Modes of offline validation:
- Full offline mode validation – Tag database and validation rules from the controller are stored in DC memory, and used for validation when the controller is offline.
Cached mode validation – A tag will be allowed if it appears in the DC’s transaction cache as allowed, within the last week. If the tag is presented during cached offline mode, and it has not appeared in the DC transaction buffer for the last week, it will be denied unknown.
Conditions for offline mode selection by system/controller:
- If the site has more than 10000 active tags, all door controllers (LAN or RS485) automatically go into cached mode validation.
- All door controllers connected via RS485 where there are more than 1000 active tags on the site, automatically go into cached mode validation.
- All door controllers connected via LAN where there are less than 10000 active tags on site automatically use full offline validation.
- Where there are less than 1000 active tags per site, all door controllers (LAN or RS485) automatically use full offline validation.
- EC3 special case: Door controllers connected via RS485 where there are less than 10000 active tags still use full offline mode validation.
Limitations of DC module:
- Only 4 reader modules are supported per DC module in offline mode (DC FW v2.00 or higher required). Any additional modules connected to the DC module will cease to function if the system controller goes offline. This applies to the cluster bus and S-Bus.
- When offline, the only actions which take place on a tag presentation are those on the module where the tag was presented so the across module relay actions do not take place, only the buzzer and LED actions occur on the same module.