FieldServer FS-8704-49 instruction manual Data Aire Description, Performance Issues Dartiii only

FS-8700-49_Data_Aire_DAP Page 4 of 48

1.Data Aire Description

The Data Aire Driver is capable of direct connection to a network of Data Aire DAP devices. The FieldServer is connected in a RS-485 loop topology. Two FieldServer ports are required per loop. The driver is an active client. All data is obtained by poll & response.

Connection to a DART is not supported by this driver.

The driver may be configured very simply (See Section 4.4). configurations are also available and are described in Appendix B. common message formats for common Data Aire DAP devices. messages is provided in the manual.

A number of advanced The driver supports the A list of the supported

The information that follows describes how to expand upon the factory defaults provided in the configuration files included with the FieldServer.

1.1.Performance Issues - DARTIII only

Data Aire communication is based on a very low baud rate. In addition inter-message timing constraints and overhead requirements for active messages in a Dart configuration add significant time to each transaction. It is not possible to write a setpoint to a device until the device has been successfully read, and the result of the write will not be seen until the next read is complete. The result of a write may not be seen for some time due to slow communications and significant inter poll delays.

1.2.Data Alarm Network Module Network LED Operation

DAP-II units communicate with a DART unit by using a Data Alarm Network Module. This module provides a RS-485 communications link. Installed on the card are several LEDS. The table below explains how the LEDS appear under normal (correctly functioning) operation.

LED	LED Appearance
	The Network Module has a blown fuse detection circuit. If one (or more) of
FUSE	the fuses has an open circuit, then the FUSE LED will be lit. Normally, this
	LED is dark.
	Communications signals enter and leave the Network Module. These LEDS
DS1 &	reflect the communications activity. When first powered up, both LED's will
	be lit and the illumination will be steady. As the DART communicates with
DS3
	the network, both LED’s will begin to flicker in unison. All of the Network
	Module LED’s will flicker at the same time.
	At some point the DART will send a communication message to a specific
	network-connected DAP-II that requires a reply to the DART. If the message
	is received without error, the DAP-II will reply by engaging a relay on the
NETWORK	Network Module and transmitting a message. When this happens the
	NETWORK LED will come on. Whenever a NETWORK LED is seen to
	come on it means that the communications into the Network Module is
	satisfactory. It is still possible to have a wiring problem downstream of the
	module that prevents the message from being received by the DART

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