Gpib Card If-G1; Notes About The Communication; Terms Explained; Differences To The Other Interface Cards - Elektro-Automatik IF-U1 Benutzerhandbuch

About the interface cards

4.5 GPIB card IF-G1

The interface card IF-G1 offers a standardised, digital in-
terface (GPIB) according to IEEE 488.1/. Its installation is
described on the short install guide that is included in the
package.
In case a second card is used inside a device of the series
PSI 9000, the IF-G1 can only be combined with the analogue
card IF-A1 or the digital cards IF-R1 and IF-U1. It must not
be plugged together with the CAN interface card IF-C1!

4.5.1 Notes about the communication

This card does not use the object orientated communication
protocol, it uses the internationally standardised SCPI com-
mand set. SCPI uses plain text in ASCII format, which can
simplify programming.
4.5.2 Controlling a device via GPIB
In principle, the procedure to access and control our devices
is the same as with the other digital cards. Once the GPIB
card is connected to a PC and has been configured, you
can easily query status and actual values from the device.
Controlling the device, like setting the input/output on or off
or sending set values, requires to activate the remote control
mode. This doesn't happen automatically. The corresponding
commands are described below.
Note: with GPIB you can link only up to 15 units on one
bus!

4.5.3 Terms explained

GPIB General Purpose Interface Bus
IEEE60488.1 standardises GPIB interface to a host
computer (older synonyms: IEC bus, IEC
65 bus , ANSI standard MC1.1)
SCPI Standard Commands for Programmable
Instruments => a standardised command
language for communication with instru-
mentes, measuring equipment etc.

4.5.4 Differences to the other interface cards

For the communication connection to the host computer
(PC, SPC or similiar) a GPIB interface and the text based
command set SCPI are used. The protocol differs very much
from the other interface cards IF-xx. These are all using an
object orientated, not standardised communication protocol,
which has been unified for any other digital interface card.

4.5.5 Firmware updates

The package includes a flat ribbon cable that is used for
firmware updates of the microprocessor. In order to update,
plug the cable to X5 on the PCB, insert the card carefully
into the device again and connect the Sub-D plug to a PC
via a 9pole Sub-D cable of „null modem" type. A seperately
obtainable update tool can either be downloaded from your
supplier's website or is obtained by request.
© 009, Elektro-Automatik GmbH & Co. KG

4.5.6 Transmission and execution times

The SCPI protocol needs to be translated into the internal
one and thus consumes some time.
The protocol translation time and the execution time of
the device's internal microcontroller are dependent on the
command and have to be added to the transmission time.
Typical values are:
Time of protocol translation T
Transmission time to the internal
microcontroller T : 0.5ms
T,MC
Execution time of the internal
microcontroller T : ms
E,MC
In case the host PC is expecting a response, a total time of
= + + +
T T T T T
Request T GPIB , P T MC , E MC
= + + • +
T T 0,2 T T
Response T MC , P T GPIB ,
command sent.
The transmission time T
GPIB
lies at typical 200μs. The recommended command interval
time is >30ms. Smaller times can lead to execution errors.
4.5.7 Configuring the IF-G1
The card is configured in the setup menu.
Note: it is definitely necessary to choose a unique
node" (=address) for every unit that is connected to the same
PC. Only then the device can be identified and addressed
correctly. Accessing the setup menu:
M
+ Communication +


device node
= {1..30} One out of 30 device nodes can be set
Remind, that only 15 units can be used on
one bus line!

Slot A : { IF-... } depends on the card type

Slot B : { IF-... } depends on the card type
Here you can set the device node and get an overview of the
installed card(s). In case the settings are changed without
restarting the device, you are required to send the *RST
command in order to submit the new settings.
Attention! At power supply series PSI 9000 up to firmware
version 3.04 resp. at electronic load series EL3000/9000
upto firmware version 2.11, the interface card is detected as
„IF-C1", i.e. as CAN card. Then it must be set to 100kBd, no
bus termination and RID = 0, in order to work. From firmware
version 3.05 (PSI) resp. 2.12 (EL) on the card is detected
correctly as IF-G1.
: ms
P
,
can result, depending on the
of the GPIB bus is very short and
Default: 1
EN
„device
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