Internal Registers; Concepts; Figure 3.4 Enable Registers - ILX Lightwave FPM-8200 User Manual

Internal Registers

Internal registers are used to inform the control program of events and conditions.

Concepts

The FPM-8200 includes three internal status registers to inform your control
program of events and conditions:
• Standard event statusó8-bit register required by GPIB standards
• Event statusó16-bit register with additional event status
• Condition statusó16-bit register with condition information
For example, operation complete (event) and over-range (condition) are reported
in the appropriate bits of registers as a 1 (true) or 0 (false).
Each register is summarized into a single bit, which has an assigned place in a
"status byte" register. The status byte register has a similar summary bit that
initiates a service request.
For each register there is a corresponding enable register. Use the enable register
as a mask so only the conditions you want to check are reported in the status byte
register. This diagram illustrates the concept of enable registers:
A status register bit can only get to the input of the OR gate if a corresponding 1-
bit is available from the enable register. The summary bit then goes true (1) if any
of its inputs are true. This is why you need to use the enable register to mask off
the ones you are not interested in.
01_10
Status Register
7 6 5 4
AND
AND
AND
AND
7 6 5 4
Enable Register

Figure 3.4 Enable Registers

R E M O T E O P E R A T I O N
Internal Registers
3 2 1 0
AND
AND
AND
AND
3 2 1 0
C H A P T E R
Summary Bit
OR
FPM-8200
3
31
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