Omega Vehicle Security 1400 manual Ieee 488 Serial Poll Response, Service Request Enable Register

Registers, Data Formats, & Queries			Appendix C
Bit Location	Description	Set, Clear and Descriptive Information
DI01	Alarm	Set when the scanning device has sensed a valid alarm condition. The alarm is
		cleared when the alarm condition no longer exists.

DI02 Trigger

Detected

DI03 Ready

Set when ChartScan has detected the trigger condition and will be cleared when the acquisition is complete or the trigger has been reconfigured.

Set when ChartScan is ready to process another command. It is cleared when the unit is processing a command line. This bit should be examined with a serial poll prior to issuing a new command line. This allows any detected errors to be traced to the specific command line containing the error. If all the setup information for a specific ChartScan operation is included in one line, this bit also indicates when all processing is done and the X command is completed. This ensures the unit has completely processed all state changes before initiating any further activity.

DI04	Scan	Set when at least 1 acquisition scan is available in the acquisition buffer to be read.
	Available	Cleared when there are no scans available in the buffer to be read.
DI05	Message	Set when the output queue is not empty. It is cleared when the output queue is
	Available	empty. This bit reflects whether any command responses are still in the output
	(MAV)	queue.
DI06	Event Status	Reflects the logical OR of all the bits in the Event Status Register (ESR) ANDed
	Register Bit	with their equivalent enable bits in the Event Status Enable (ESE) register. If this bit
	(ESB)	is set, at least one bit in the ESR is set and has its corresponding enable bit in the
		ESE set. The status command U0 can be issued to read the ESR. See the
		following for more information on ESR and ESE.
DI07	Service	Set when ChartScan requests service. It is cleared when a SPOLL is performed.
	Request Bit
	(SRQ)
DI08	Buffer	Set if a buffer overrun occurs. It is cleared when the buffer becomes empty by
	Overrun	either reading out the contents of the buffer or performing a Reset (*B) of the buffer.

Service Request Enable Register

The service request enable register controls which bits of the status byte register are to be reflected in the Request for Service and Master Summary Status bits of the status byte register. As shown in the figure on page C-14, the bits of the status byte register are logically ANDed with the corresponding bits of the service request enable register. The resulting bits are logically ORed together to form the master summary event status bit (MSS) in the status byte register and to control the request for service (RQS) bit in that register. The service request enable register does not affect the status byte register; it only affects the MSS and RQS bits of the status byte register. The event status enable register is set and interrogated with the Mn command.

IEEE 488 Serial Poll Response

The Serial Poll Status Byte is sent when a serial poll (SPoll) command is received over the IEEE488 bus from the active controller. Although these bits are always set to indicate ChartScan’s status, they do not generate an SRQ on the IEEE488 bus unless the corresponding enable bit in the Service Request Enable (SRE) register has been set with the Mn command. Below is a description of each bit in the Serial Poll Status Byte Register.

Bit Location	Value	Description	Bit
DIO1 (LSBit)	1	Alarm	1
DIO2	2	Trigger Detected	2
DIO3	4	Ready	3
DIO4	8	Scan Available	4
DIO5	16	Message Available(MAV)	5
DIO6	32	Event Status Register Bit (ESB)	6
DIO7	64	Service Request Bit (SRQ)	7
DIO8 (MSBit)	128	Buffer Overrun	8

All bits in the serial poll status byte register are cleared by either a *R command, which returns the ChartScan to its power-up default conditions, or a read of the serial poll status byte register via the Status command U1.

C-16 ChartScan User’s Manual