Tektronix DMM4020 Digital-Multimeter, DMM, VFD-Multiple segment, 20000 counts CAT II 600 V DMM4020-A1 Data Sheet

 

 

 

 

4

 

  

4-3 

This chapter describes how to set up, configure and operate the Meter via the RS-232 

computer interface on the Meter’s rear panel. The Meter can be operated from a host (a 

terminal, controller, PC, or computer) by sending commands to the Meter through its 

computer interface. 
An annotated sample program illustrating the use of the RS-232 computer interface is 

provided at the end of this chapter. Refer to Chapter 3 for complete descriptions of all 

Meter functions and features. 
This chapter assumes that you are familiar with the basics of data communication and 

RS-232 interface. 

When the Meter is operated from a host, it is said to be operated remotely. When the 

Meter is operated from its front panel, it is said to be operated locally. 
Most operations that can be performed locally can also be performed remotely using the 

computer interface. Some operations, like setting communications parameters for the RS-

232 interface operations, can only be performed from the front panel. 

The Meter comes equipped with an RS-232 (serial) interface. Using the interface turns 

the Meter into a fully programmable instrument that can be integrated into an automated 

instrumentation system. 

The RS-232 interface allows ASCII asynchronous serial communication between the 

Meter and a host, serial printer or terminal. 

Table 4-1 provides the RS-232 communication parameters factory settings. Setting RS-

232 communication parameters is only performed through the front panel. 
In order for the Meter and host to communicate via the RS-232 interface, the 

communication parameters of the Meter must match those of the host. If the 

communications parameters of the host and Meter do not match, set the appropriate baud 

rate and parity parameters as follows: 

1.  Press P to turn the Meter on. 
2.  Press Q then K. The baud rate currently selected is shown in the primary 

display and baud is shown in the secondary display. 

3.  Press U or V to scroll to the desired baud, and then press R to set the 

RS-232 baud rate. 

4.  Press U or V to scroll to the desired data bit (7 or 8) selection, then press 

R

 to set parity. Echo appears on the secondary display, and 0n or 0FF appears 

on the primary display.  

5.  To select an Echo mode, press U or V to select On or OFF, and then press 

R

 to set the selected Echo state. When Echo is on, each command sent to the 

Meter over the RS-232 interface is echoed to the host's display screen. When 

Echo is off, commands are not echoed.