Using the RS-232 Computer Interface, Introduction

Using the Computer Interface	4
Introduction

Introduction

The instrument can be operated from a host via commands sent through the rear panel computer interface. The host can be a terminal, controller, PC, or other computer.

This chapter describes how to set up and operate the instrument via the RS-232 interface (standard with Hydra Series II Data Acquisition Unit and Hydra Series II Data Logger) or the IEEE-488 computer interface (optional with Hydra Series II Data Acquisition Unit only.) The RS-232 interface can also be connected to a serial printer for direct output of data in printed format.

With the IEEE-488 computer interface installed in the Hydra Series II Data Acquisition Unit, the instrument is fully programmable for use on the IEEE Standard 488.1 interface bus (1987). The instrument is also designed in compliance with supplemental IEEE Std. 488.2-1987.

This chapter assumes you are familiar with the basics of data communication, the RS-

232interface, and/or the IEEE-488 bus. For an introduction to the IEEE-488 interface, request Fluke Application Bulletin AB-36, "IEEE Standard 488-1978 Digital Interface for Programmable Instrumentation."

An annotated sample program, illustrating the use of the RS-232 computer interface, is provided at the end of this chapter. Calibration procedures using the computer interface are provided in the Hydra Series II Service Manual (P/N 110731).

Front Panel and Computer Interface Operations

When the instrument is operated from the front panel, it is said to be under front panel control. When the instrument is operated from a host, it is said to be operating under computer interface control.

Most operations that can be performed from the front panel can also be performed over the computer interface. Some operations, like setting communications parameters for the RS-232 interface and selecting the instrument address for IEEE-488 operations, can only be performed from the front panel.

Types of Computer Interface

Only one interface can be selected or used at a time.

The optional IEEE-488 interface is contained on a single printed circuit assembly and can be selected if it is installed in the Hydra Series II Data Acquisition Unit. The IEEE- 488 interface cannot be used with the Hydra Series II Data Logger. Of course, the RS- 232 interface can be re-selected even if the IEEE-488 interface is installed.

If you are going to use the RS-232 interface, continue reading. If you are going to use the IEEE-488 interface, skip to "USING THE IEEE-488 INTERFACE" later in this chapter.

Note

To determine which computer interface is enabled, select COMM (K

L). If "IEEE" appears on the display, the IEEE-488 interface is enabled.

Otherwise, if a baud rate appears, the RS-232 interface is enabled.