Remote Command Emulation
Is remote command SCPI emulation limiting your measurement capacity?
Programming automated test systems:
In order to control a sequence of tests or routines, controllers will send and receive ASCI
text based instrument commands across the IEEE-488.2 interface bus to and from a variety
of test equipment.
The most widely used standard, IEEE-488.2 was adopted by many manufacturers in early 1980s:
The IEEE-488.2 standard specified a common command set for test and measurement equipment. This command protocol standard was called SCPI – Standard Commands for Programmable Instrumentation.
Outside of SCPI, many manufacturers developed their own command set making it difficult, if not impossible to replace an instrument programmed in an automated test system.
Test & measurement equipment remote command emulation:
- Manufacturers now often include a Remote Command Emulation mode in order to replace legacy equipment that has been discontinued.
- Remote commands will, as far as possible, match the corresponding remote commands of the legacy instrument.
- However, differences in hardware often create limitations that may not be overcome. These fall in two categories: ASCII Command, and analog measurement process emulation.
Some ASCII Command set emulation limitations:
- *ID?: System query command used to identify the make, model, serial number, and version instrument. Some instruments provide a function to custom program the ID text response string, overcoming this limitation.
- Trigger Modes: Most instruments have several trigger operating modes, like continuous, single, delay, event count and more. Differences in instrument design may pose limitations.
- Hardware error response messages.
Some secondary measurement limitations that must be considered are:
- Differences in measurement range span. For example, a legacy meter may span 20,000 counts, while the replacement spans 12,000 counts.
- A measurement of 1.5 volts in the legacy meter will be in the 2 volt range, while the new meter will jump to 20 volt range, impacting the resolution and measurement uncertainty.
- Trigger delays and timing may vary.
- Measurement reading throughput rates and timing may vary.
Consult the manufacturers documentation to identify any limitation and possible workarounds.
Fluke 88XX DMM Emulation Guide