Automatic mp1570a of SDH error-correcting instrument

MP1570A is a BER tester used by Nippon Corporation for SDH testing.

Automated test scenarios and principles for 1.mp1570a

arbitrary test pc--(telnet)--Test PC (TCL Interrupt)-->sig_teq_sdh.tcl--> (GPIB line)-->mp1570a chassis

MP1570A's situation is unique, first of all its chassis internal software architecture uses the Visa virtual instrument software architecture. So its chassis does not have an IP address, the PC cannot be connected to the chassis via an Ethernet cable, and can only be connected via the GPIB line. The chassis internal command uses the SCPI programmable instrument standard command. Agilent's instruments seem to be using this set.

Because I used to do all is Ethernet, write this library really is learning from the beginning, very troublesome. While the job requires that the AT function is not very complex, it takes more time than before. But also learned a new field. After the closing principle is understood, it is much easier to expand later.

VISA:
Virtual instrument Software Architecture, is the VPP unified development of the I/O interface software standards and related specifications, this I/O library is called the Visa library (standard I/O function library for instrument programming), placed in the PC directory, is the standard software communication interface between PC and instrument, It realizes the control of the instrument by PC. It realizes the configuration and programming of the instrument using GPIB,VXI,PXI, serial port (rs232/485), Ethernet, usb,ieee1394 and other interfaces.
VISA is broadly divided into 2 types: Ni-visa Agilent-visa
MP1570A is using Agilent's Agilent-visa drive .

Gpib:
GPIB Universal Interface Bus, many peripherals such as some instruments built-in GPIB control chip and control card. Connect via GPIB Line and GPIB port to control PC. The transmission rate is higher than the serial port. and is programmable
GPIB is also the International General Engineering Control Protocol that HP proposes, IEEE488. The electrical, mechanical, functional and software characteristics of the connection system between PC and programmable instruments are defined

SCPI:
SCPI (programmable instrument standard instruction set, consisting of ASCII characters), can be used for a variety of interfaces such as GPIB,VXI,LAN,USB, serial RS232 ...

It is a hardware-independent pure software standard, is based on the existing standard IEEE488.1 and IEEE 488.2, and follows the IEEE754 standard floating-point arithmetic rules, ISO646 information exchange 7-bit encoding symbols (equivalent to ASCLL programming) Standardized instrument programming languages such as various standards.

The specific SCPI instruction set is introduced separately, here is skipped.

In general mp1570a Automation principle is similar to Xena, but with chassis is not through the socket connection, but through the GPIB line connected to the chassis visa address, issued SCPI command to operate the hardware, and it has no visual return results and reports, The at effect is not particularly good.

2.mp1570a at considerations

(1) Test PC needs to install Agilent Connection expect_ (Agilent Connection Specialist installation package), after the installation of Agilent Library, C:/Program files/directory will appear agilent,visa two directories.

(2) need to use TCL's two third-party library Msgcat.tcl,tcom.tcl&tcom.dll, can be placed under their own package under the separate Library directory for easy portability. The following two sentences are written in the Pkgindex.tcl file of the package:

Package ifneeded tcom 3.9 [list load [file join $dir/library/tcom "tcom.dll]]\n[list source [file Join $dir/library/tcom [TCOM.TCL]]
Package ifneeded msgcat 1.4.1 [list source [file Join $dir/library/msgcat1.4.1 "MSGCAT.TCL]]

(3) Write the library file also use tcom library:: Tcom::import load Agilent-visa Library from GlobMgr.dll, the code is as follows:

set Agilentlib "C:/Program Files/visa/visacom/globmgr.dll"
# tcom:: The Tcom::import command creates a new command from the. DLL type library, returning the namespace name, which is the type library name
#:: Tcom::import $agilentLib load Agilent Library, perform successful return: Visacomlib
if {[Catch {set RET [:: Tcom::import $AgilentLib]} rst]} {
puts stderr "$rst: couldn ' t read file $AgilentLib for SDH TEQ"
} else {
#VISA中也是使用句柄来作为资源唯一逻辑标识符, length 4 bytes
set RM [:: Visacomlib::resourcemanager]; #执行成功返回::: tcom::handle0x0231f770 Create a resource manager instance
set Fmio [:: visacomlib::formattedio488]; #执行成功返回::: tcom::handle0x0231f6f0 set up a device instance
           } 

Automatic mp1570a of SDH error-correcting instrument