Device configuration consists of assigning an AS-Interface Device Type to the device and assigning the device address. An AS-Interface Device Type is a fixed-format description of the device that the AS-Interface master uses to communicate with the slave device. You create your own AS-Interface Device Type from the device's data sheet. The AS-Interface Device Type consists of an Identification code and I/O Configuration (taken together these are defined by the AS-Interface Specification as the device Profile) the Parameters for the device, and the inputs and outputs supported by the device. (In the DeltaV Explorer, the Profile appears in the format S-[I/O Configuration].[Identification Code] as defined by the AS-Interface Specification. For example, S-2.0.) The Identification code and I/O Configuration are designated by the device manufacturer. The Identification code identifies the type of device and the I/O Configuration identifies the device's input and output bits. The four bit Parameters are used to customize the device behavior.
An AS-i port status value of Mismatch in DeltaV Diagnostics means that the profile for one or more of the actual devices on the segment does not match that of the configured device.
When a new AS-Interface slave device is created in the DeltaV Explorer, each input and output for the device is assigned a channel label and a Device Signal Tag (DST). The labels and DSTs appear under the device in the Explorer hierarchy. A Device Signal Tag is a unique name that represents a specific signal from the device. The signal is used in the control strategy. A default DST name is assigned by the system when the device is created but you can rename it at any time. The channel label is taken from the device's AS-Interface Device Type and can be modified through the AS-Interface Device Type's Properties dialog. Refer to the Port Downloads section for information on downloading the AS-Interface ports.
Modifying Devices
Use the device's Properties dialog to modify the description, address, and to enable and disable the device. Select the device in the DeltaV Explorer and select Properties from the device's context menu to access the Properties dialog. The Add New Type button on the Properties dialog is functional only when adding a new device to the DeltaV system; not when viewing the properties of an existing device. Use the online help for help on the fields in the Properties dialog.
Addressing
Each slave device connected to an AS-Interface network has an address between 1 and 31. All AS-Interface devices are shipped from the manufacturer with address 0 – a temporary address that prohibits data exchange. A new AS-Interface slave device is assigned an address when it is created in the DeltaV Explorer. When a device is replaced, it can have its address assigned through a handheld device or it can be automatically set to the original address through the Auto Address feature on the AS-Interface master.
Auto-Sensing
The auto-sense feature aids in AS-Interface device configuration. Auto-sensing lists the slave devices existing in the database and those sensed on the port and shows each device's address, name, I/O configuration, and Identification code. This feature can be used to add devices to the configuration, and to clear and set addresses. You must download the port to activate slave devices.
Turn off the Auto-address enable feature before attempting to clear an address.
Port Downloads
The action that the AS-Interface master takes following a new port download depends on the changes included in the new configuration. Changes to port properties: Auto address enable and Action in the event of controller failure are copied to the master and there is no effect on the slave devices on the network.
WARNING!If a slave device is added or removed from the configuration or if a slave address or profile is changed, the AS-Interface master must restart the port. Restarting the port consists of the master transitioning to the offline state where it resets all slave devices and reactivates the slaves. Resetting the slave devices causes the slaves to deactivate their outputs. Once the port restarts, slave outputs return to the controller-driven state.