2635A
Users Manual
4-16
For example, an IER byte of binary 10000000 (decimal 128) indicates Scan Complete. If
the IEE register is set to binary 10000000 (using the command IEE 128), then a Scan
Complete condition will cause the Logical OR gate to output a logic high. In a similar
manner, parameters can be combined. An IER byte of binary 10000101 (decimal 133)
and an IEE set to a corresponding binary 10000101 (using the command IEE 133), will
cause the Logical OR gate to have a logic high output for any of three conditions: Scan
Complete -or- Open Thermocouple -or- Alarm Limit Transition.
Other commands include IER?, which returns the decimal equivalent of the IER byte and
then clears the register to zero, and IEE?, which returns the decimal equivalent of the
IEE byte. The command *CLS will clear all event registers. (See Appendix E for an 8-bit
binary-coded-decimal table.)
Table 4-1. Instrument Event Register (IER)
Bit Name Description
0 ALT Alarm Limit Transition. Set high (1) when any measurement value has
transitioned into or out of alarm. Alarms are defined through the front
panel or the computer interface (ALARM_LIMIT). This bit is cleared when
read with IER? and when alarms or review values are cleared.
1 TOB Totalize Overflow. Set high (1) when the Totalizer overflows (65,535). This
bit is cleared when read with IER? and when the Totalizer is zeroed from
the front panel or set to some other non-overflow value (,65,535) with the
computer interface TOTAL command.
2 OTC Open Thermocouple. Set high (1) when open thermocouple checking is
enabled (with TEMP_CONFIG command) and any thermocouple channel
is measured with a source impedance greater than 1 to 4 kilohms.
3 CCB Calibration Corrupted. Set high (1) when the instrument calibration data is
corrupted. When a calibration data check shows a corruption of calibration
data, the calibration alarm bit remains set in the Instrument Status
Register until the instrument is recalibrated.
4 CNC Configuration Corrupted. the instrument configuration stored in NVRAM
has been found to be corrupted. The RAM CRC is no longer valid.
5,6 not used Always set to 0.
7 SCB Scan Complete. Set high (logic 1) when a measurement scan has been
completed. This bit is cleared when read with IER?
NOTES
Whenever the Instrument Event Register is read, the condition bits are cleared.
This register is used in conjunction with the Instrument Event Enable Register to determine the
conditions under which the Instrument Event Bit of the Status Byte is set.
Standard Event Status Register (ESR)The inputs to the Standard Event Status Register (ESR) include Power On, Command
Error, Execution Error, Device Dependent Error, Query Error and Operation Complete.
Each input is described in Table 4-2. The output byte of the ESR is ANDed with the
output byte of the corresponding Standard Event Status Enable (ESE) register. When
there is logic high correlation between any of the bits of the ESR and ESE registers, the