Product Manual

291, 292, 294
Users Manual
17-8
The bits in the PPE command are as follows:
bit 7 =
x don't care
bit 6 = 1
bit 5 = 1
bit 4 = 0
parallel poll enable
bit 3 = sense sense of the response bit; 0 = low, 1 = high
bit 2 = ?
bit 1 = ?
bit 0 = ?
bit position of the response
For example: to return the RQS bit (bit 6 of the Status Byte Register) as a 1 when true
and a 0 when false in bit position 1 in response to a parallel poll operation, send the
following commands:
*
PRE 64<pmt>, then PPC followed by 69H (PPE)
The parallel poll response from the generator will then be 00H if RQS is 0 and 01H if
RQS is 1.
During parallel poll response the
DIO interface lines are resistively terminated (passive
termination). This allows multiple devices to share the same response bit position in
either wired-AND or wired-OR configuration, see IEEE 488.1 for more information.
Status Reporting
This section describes the complete status model of the instrument. Note that some
registers are specific to the GPIB section of the instrument and are of limited use in an
RS232 environment.
Standard Event Status and Standard Event Status Enable Registers
These two registers are implemented as required by the IEEE std. 488.2.
Any bits set in the Standard Event Status Register which correspond to bits set in the
Standard Event Status Enable Register will cause the ESB bit to be set in the Status Byte
Register.
The Standard Event Status Register is read and cleared by the
*
ESR? command. The
Standard Event Status Enable register is set by the
*
ESE <nrf> command and read
by the
*
ESE? command.
Bit 7 Power On. Set when power is first applied to the instrument.
Bit 6 Not used.
Bit 5 Command Error. Set when a syntax type error is detected in a command from the
bus. The parser is reset and parsing continues at the next byte in the input stream.
Bit 4 Execution Error. Set when an error is encountered while attempting to execute a
completely parsed command. The appropriate error number will be reported in
the Execution Error Register.
Bit 3 Not used.
Bit 2 Query Error. Set when a query error occurs. The appropriate error number will
be reported in the Query Error Register as listed below.
1. Interrupted error
2. Deadlock error
3. Unterminated error
Bit 1 Not used.
Bit 0 Operation Complete. Set in response to the
*
OPC command.