Keithley 6512, Instruction Manual, Page: 64 / 156

IEEE-488 Programming
3-9
Examples K1X EOI disabled, hold-off enabled.
K3X Both EOI and hold-off disabled.
3.2.7 Non-volatile memory storage (L)
Purpose
To store calibration constants in NVRAM.
Format L1
Description
The Model 6512 uses non-volatile (NV) RAM to store calibration parameters. Once the instru-
ment has been calibrated, as described in the last paragraph, the NVRAM storage command
should be sent to permanently store these parameters. This procedure is performed by sending
the following sequence: L1X. NVRAM storage will take place when the instrument receives this
command over the bus. Note that NVRAM storage may be disabled by changing the position of
a calibration jumper, as described in Section 7. If the jumper is in the enabled position, all cali-
bration must be properly done, or calibration of all functions and ranges will be affected.
Programming Do not perform the programming example below unless actual NVRAM storage is desired. Un-
Note
less proper calibrating parameters have been previously programmed, inadvertent use of this
command could affect instrument accuracy.
Example
L1X Perform non-volatile RAM storage.
3.2.8 SRQ mask (M) and status byte format
Purpose
To control which instrument conditions will cause the unit to generate an SRQ (Service Re-
quest).
Format
M0 SRQ disabled
M1 Reading overflow
M2 Data store memory full (100 readings)
M8 Reading done
M16 Ready to accept bus commands
M32 Error
Default
Upon power-up, or after receiving a DCL or SDC command, SRQ will be disabled (M0).
Description The SRQ command controls which of a number of conditions within the Model 6512 will cause
the instrument to request service from the controller by asserting SRQ. Once an SRQ is gener-
ated, the status byte can be checked to determine if the Model 6512 was the instrument that as-
serted SRQ, and, if so, what conditions caused it to do so. Note that additional data and error
conditions can be checked by using the U1 and U2 commands, as described in paragraph 3.2.13.
SRQ Mask
The Model 6512 uses an internal mask to determine which conditions will cause an SRQ to be
generated. Figure 3-2 shows the general format of this mask, which is made up of eight bits. The
SRQ mask has the same general format as the status byte (described below) except for the fact
that bit 6 is not used in the SRQ mask.