G3 ASD (tacAsd) driver setup basics.


Provides additional setup information for the G3 ASD (tacAsd) driver implementation.

Product Line

TAC I/A Series


G3 ASD (tacAsd) driver (all revisions)




G3 ASD (tacAsd) driver setup basics ...

Monitor properties

Ping Enabled = true
Ping Frequency = 5m change to 1m
Alarm On Failure = true
Startup Alarm Delay = 5m

The baud rate sync properties is the mechanism that synchronizes the baud rates for the ASD bus. Upon reset, ASD devices initialize to 1200 baud and it is this mechanism that locates those devices and sets the baud rate to 19.2K or 9.6K (if PEMs are used on the bus). These values are part of the ASD specification and should not be changed.

Last Time Sync is the last time a successful sync occurred
Baud Rate Sync Time = 1m
Baud Rate Set Timeout = 0.2s
Baud Rate Set Repeat = 1
Baud Rate Change Millis = 800

Total Devices indicates the total number of devices active.
Total Down indicates the total number of down devices.

Scan Time indicates the total time to poll through the list if devices. The ASD communications protocol is designed to exchange most data between the host (ENC) and device with one transaction. This means that typical data (e.g. EMS, etc.) is written to the device as part of the request and response data (e.g. Window, Output, Diagnostics, etc.) in one transaction. In this case, the scan time is 6.9 seconds for 33 devices or approximately 4.5 devices per second.

Tuning Policies (Default Policy)

Min Write Time = 0
Max Write Time = 0
Write On Start = false
Write On Up = false
Write On Enabled = false
Stale Time = 0

Note: The stale time actually involves the proxy point objects. The polling mechanism still continues and the internal point information is still updated. The driver does not implement the interaction between the point updates and proxy point stale. The values should be left at their default settings.

Poll Scheduler

Poll Enabled = true

Fast Rate = 5s (defaults to 1s)
Normal Rate = 10s (defaults to 5s)
Slow Rate = 30s (defaults to 30s)

Typically set the Normal Rate based upon the rules specified in the R2 documentation or (Normal Rate seconds = Number of devices / 3.5). For example, a network with 33 devices would be set to (33 / 3.5 = 10 seconds). As indicated earlier, the driver inherits the basic driver properties and mechanisms. G3 implements a complex poll scheduling mechanism that automatically determines and continually adjusts the poll list to achieve the most efficient polling.

Retry Count

The retry is only used in the event that a response from an ASD device is not received.  This value defaults to 1 and can be increased if needed to a maximum of 3 if devices are unable to respond to the initial message and one subsequent retry,  Devices that do not respond to the initial message may indicate a potential issue with the ASD bus.

Response Timeout

This is the amount of time the driver will wait for a response to a request before retrying the request.  This value defaults to 2 seconds and should not be changed.

Inter Message Delay

This value defaults to 0 seconds and should not be changed.