Introduction - Keithley 6430 Instruction Manual

G-2 GPIB 488.1 Protocol

Introduction

The Model 6430 supports two GPIB protocols: SCPI and 488.1. The 488.1 protocol is
included to significantly increase speed over the GPIB.
When using the 488.1 protocol, throughput is enhanced up to 10 times for data sent to the
Model 6430 (command messages) and up to 20 times for data returned by the Model 6430
(response messages). The speed of readings sent over the GPIB is also increased; see GPIB
reading speed comparisons at the end of this Appendix for details.
NOTE
Selecting the 488.1 protocol
Perform the following steps to select the 488.1 protocol:
1.
2.
3.
4.
5.
6.
When switching between the SCPI protocol and 488.1 protocol, the instrument does not
reset. The GPIB protocol setting is saved in EEPROM, and the unit will power up with that
selected protocol.
The GPIB protocol cannot be changed over the bus. However, there is a query command to
determine the presently selected protocol. When the 488.1 protocol is selected, the message
exchange protocol (MEP) disables. Therefore, if you use the following query to request the
state of MEP, you will know which protocol is enabled:
:SYSTem:MEP[:STATe]?
If a "1" is returned, MEP is enabled, and the SCPI protocol is selected. A "0" indicates that
MEP is disabled, and the 488.1 protocol is enabled. To summarize:
1 = SCPI protocol
0 = 488.1 protocol
With the 488.1 protocol selected, you will still use SCPI commands to program the
Model 6430. Operation differences between the two protocols are discussed in this
appendix.
Press MENU to display the MAIN MENU.
Place the cursor on COMMUNICATION, and press ENTER to display the
COMMUNICATIONS SETUP menu.
Place the cursor on GPIB, and press ENTER to display the present GPIB address.
Press ENTER to display the GPIB PROTOCOL menu.
Place the cursor on 488.1, and press ENTER.
Use the EXIT key to back out of the menu structure.