Getting started with the gpib – ETS-Lindgren 2090 Controller User Manual

Page 74

Using the GPIB Command Set with the Model 2090

Model 2090 Multi-Device Controller

IEEE 488.2 standard does not allow one behavior of the

older controllers. Sending a position or limit command

would set up the controller to respond to all future reads

with that value. The IEEE 488.2 standard requires a

query/response behavior, where the returned value must be

requested first. Thus, on the model 2090, all GPIB reads

must be preceded by a write of the associated query

command to the device. Programs designed to write the

command once and read the result (usually the current

position) over and over will not work without modification.

GETTING STARTED WITH THE GPIB

The Model 2090 contains a single GPIB port which has

been configured to accept two separate addresses. Valid

addresses are in the range of 0 to 30, although 0 is typically

reserved for the controller in charge (i.e. the PC). There are

no criteria for setting the addresses, other than that they be

different from each other, but it is recommend that the

address for Device 1 be one address less than for Device 2.

The default settings are 8 and 9.

NOTE (on using the N1/N2 numeric modes): Once a mode

is selected, it is effective for both devices. N1 mode is

backward compatible for the older model ETS-Lindgren

controllers, 1050, 1060, and 1090. This mode causes the

GPIB to respond to queries with only a 3 digit value which

was the maximum resolution of the older controllers. The

N2 mode allows one to access the higher degree of display

resolution available with the Model 2090 controller. This

will give a floating-point response, XXX.X. Note that N1 is

Revision G– P# 399199