AIDA IEEE488 Component

The IEEE488 component is a hardware driver component. The Windows version of the IEEE488 component requires the presence of a National Instruments IEEE488 board and the appropriate drivers.

Remarks

Communication Status

The IEEE488 board has to be the active controller (Controller-in-Charge) to send data. This can be achieved by setting the AIDA_nStartCommu flag in the dwFlags member of the AIDA event. When an error occurs while starting the communication an AIDA event with the flag AIDA_nCommuStartError will be generated, when the communication could be established the flag AIDA_nCommuStarted will be set.

When errors occur the controller becomes inactive. The change of the communication status will be signaled in received events by the flags AIDA_nCommuStarted and AIDA_nCommuStopped.

EOI Line handling

Member bDataFlags

The bDataFlags member in the AIDA_tstEvent structure is encoded as follows:

Bit 0:	IEEE488_nDontSend	Do not send any data. This flag can be used to receive data of an AIDA event previously sent with the flag IEEE488_nDontReceive. The bits 2..3 are ignored in this case.
Bit 1:	IEEE488_nDontReceive	Do not receive any data. This flag can be used to send data without waiting for an response.
Bit 2:	IEEE488_nGotoLocal	Sets the addressed instrument to local mode. This is done after sending data of the given AIDA event. The change will take effect with the next transmission (normally reception of the instrument's response).
Bit 3:	IEEE488_nGotoRemote	This is done before sending the data of the given AIDA event. Please note that certain instruments have to be set to remote mode before certain commands are accepted.

When bDataFlags is not set valid all bits are treated as 0.

Parameters

Board

Selects the IEEE488 board used for communication. When the value is set to -1 no board is selected and the AIDA stack is offline. When the component is loaded it scans for all boards and initialises the value list for the Board parameter accordingly.

Address

Selects the default device address for communication. When the value is set to -1 no address is selected. The address can be overridden by setting the destination address in AIDA events. The address is encoded as follows:

General
Bit 0- 7:	Primary Address (PAD), Range 1..31
Bit 8-15:	Secondary Address (SAD), Range 0..127
AIDA events
Bit 8-63:	Reserved (set to 0). When setting a destination address in an AIDA event it must be valid.
Address parameter
Bit 8-31:	Reserved (set to 0). The only exception allowed is setting the default address to "no address" where all bits (0..31) are set to 1.

When selecting a board the component scans for all listeners attached to the selected board and reinitialises the value list of this parameter. Please note that this will take a few seconds.

MaxRecvLen

Maximum accepted message length when receiving data. When loading the component the range for this value will be adjusted according to the limits of the next higher component in the given AIDA stack.

See Also

AIDA Overview, list of AIDA components