User manual

73
© 2008, Elektro-Automatik GmbH & Co. KG
EN
- set_mode.vi
Sets the device mode regarding external control and standby
of the device’s output/input. There are two bits for activating
the remote mode or switch the power input/output of the de-
vice on or off. „Remote“ sets the device into remote mode.
The remote mode is required to control the device, i.e. to
set values or transfer data. Without the remote mode acti-
vated the device can only be queried to send actual values
or status data.
The remote mode can only be activated if the device „allows“
it. This depends on the current mode it is in. The local mode
or a different, special state or operation mode the device may
inhibit the activation.
Setting remote and input/output state simultaneously is not
possible!
- wr_set_values.vi
Writes the set values for U/I/P/R, according to the device type
and if remote mode is enabled. It does not send and set all
four values at once, it sends every value with its own object. If
a set value isn’t given or does not change, the corresponding
object is not sent. The input values are automatically limited
to the device properties. Too high values are set down to the
nominal value of the device. This VI sends simple message
and thus no answer is generated.
- actual_values.vi
Queries the actual values for U, I and P. They are returned
all at once, so it’s very fast. Those values always lie within
the limits of the device and should be identical to the values
displayed on the device itself.
8.1.4 Usage
For the functionality of the single VIs please also read the
LabView help file which can be found in the subfolder \data
after you have installed the VIs, or on the included CD.
Important! Following applies:
- the communication VIs (CAN.vi, USB.vi, RS232.vi, only
one usable at once), as well as the communication_layer.
vi must be used
- the communication VIs must not be placed inside a se-
quence, case or loop
- in order to contact and control a device after the communica-
tion has started, it first requires to be initialised with psi9_init.
vi resp. el_init.vi; this should only be done one time
- all other VIs can be arbitrarily used at runtime (in a loop, for
example), because the communication manages the data
flow and returns error messages, in case of problems
- parallelly placed VIs which are used to query actual values
of several devices at once are still processed subsequently,
because the communication can only contact one device at
once, even at broadcast messages; this applies for USB and
RS232, since there is no broadcast at IEEE
LabView support
8.1.2 Short info Communication VIs
The communication VIs serve as a sort of drivers for the
various bus systems, respectively interface types. These VIs
are the basis of the standard VIs. Without the communicati-
on running in the background no device can be addressed.
Hence you must use the communication VIs and start them
before any standard VI is used. Every type of interface uses
its own VI. This is just an overview about the communication
VIs, detailed information about every VI can be found in the
user manual of the VI set.
- CAN.vi
Read/write communication objects with the CAN protocol
with card IF-C1. Will not run by default, because the user has
to insert the standard CAN VIs of his CAN hardware, which
are delivered by the manufacturer of the hardware.
- RS232.vi
Read/write communication objects over RS232 (serial COM
port) with card IF-R1.
- USB.vi
Read/write communication objects over USB with card IF-
U1.
- Communication_layer.vi
Core VI of the communication, uses one of the other three
VIs.
With the VIs „RS232“ and „USB“ you can control up to 29
further devices, if the device which is connected to the PC
is configured as gateway (only PSI 9000 series) to the CAN
bus (see „4.3 CAN card IF-C1“). The gateway feature is only
recommended for low bus traffic. The direct communication
with the CAN bus from a master device (PC) is much more
efficient and faster. But this requires an extra CAN master
card in the PC.
8.1.3 Short info Standard VIs
The standard VIs are the most used VIs and are adapted to
every different type of device to suit all of its features. You
can control and configure nearly any feature of the particular
device. You can use (place) them as often as you want, but it
is only allowed to run several VIs at once if they all address
a different device.
These VIs require the communication VIs to be set up and
running.
This is just an overview about the communication VIs, de-
tailed information about every VI can be found in the user
manual of the VI set.
- init.vi
It is run once at the start of the whole application, but after the
communication VIs (which it requires to run), and initialises
the device which can be „found“. It reads out all necessary
data that is required for the whole system to work correctly
and handles them over to the other VIs.