User manual

14 GMC-I Messtechnik GmbH
Figure 2.1.6 a Pin Assignments for 9-Pin Plug and
Socket Connectors
The serial interface furnished with this KONSTANTER series is
addressable. Up to 30 KONSTANTERs can be addressed via this
interface.
Figure 2.1.6 b Interconnection via the Serial Interface
If RS 232 communication is to be expanded to several
KONSTANTERs, additional arrangements must be made
regarding data protocols.
Addressing
A separate address is assigned to each interconnected
KONSTANTER. If the KONSTANTER receives its own address, it
is switched to the “addressed” status after which it accepts all
subsequent commands and data, until it is unlisted upon receipt
of a different device address.
In compliance with IEEE 488, an address range of 0 to 31 is used,
although address 31 is reserved as a general unlist command
(UNL). The serial interface’s device address is thus identical to the
address of the optional IEEE 488 interface (if included).
Universal Commands
In addition to the command
Addr xxDevice address,
other general commands can be used which are accepted
without previous addressing.
*TRG Trigger command, synchronization
DCL Device clear
IFC Interface clear
Explanations of these commands and their syntax are included in
chapter 6.
Data Queries
If a device (slave) is requested to return data to the controller, it
may not be addressed in the interim. In other words, the controller
must wait until all requested data have been fully received. No
data may be transmitted to any other devices during this period of
time.
In the case of multiple device serial operation, good timing must be
assured. Data collision is thus avoided, which may result in
interruption of data transfer and deletion of output buffer
contents.
If the slave does not respond within a specified period of time
(TIMEOUT), the controller can try to synchronize the device with a
universal command, or execute a reset and request the required
data once again.
IEEE 488 Interface
 Up to 15 IEC bus controlled devices (including the controller)
can be interconnected to create a system.
 These devices are connected to the bus with suitable,
commercially available cables with 24-pin plug connectors.
If your IEC bus system is equipped with the previously
common 25-pin subminiature plug connectors, you’ll need a
suitable adapter cable.
In order to assure reliable data transfer, the cable length
between any two devices should not exceed 2 meters, and
overall length should not exceed 15 meters.
Double shielded connector cable is recommended if the
KONSTANTERs are operated in proximity to strong sources of
interference or their power cables.
2.2 Switching the Instrument On
After the described preparations have been completed, the
device can be switched on.
 Press the mains switch [1] at the front panel until it snaps into
place in order to turn the device on.
Power-Up Test
The microprocessor included in the device then starts a power-up
test. The following operations are performed during the test
routine (duration approximately 8 seconds):
– Reset all functional units (except battery-backed setup
memory)
– ROM test
–RAM test
– Initialize computer interfaces if installed
– Ascertain device type
– Check the A-D converter timer
– Recall last settings if required
The “LOCKED/SEQ” LED [12] blinks while this routine is running,
and all other LEDs and all digital display segments light up
(display test). If the device has been equipped with the optional
“IEEE 488 computer interface”, the selected IEC bus device
address then appears briefly at the display (e.g. “Addr 12”).
After successful completion of the self-test, the READY lamp is
continuously illuminated and the display is switched to measured
value indication for voltage (Uout) and current (Iout).
If this status is not achieved despite correctly selected device
address (0 to 30), even after repeatedly switching the device on
and off with abbreviated self-test, the device is probably
defective. If this is the case, contact your local representative.
TxD_IN 2
3
5
RxD_IN
GND_IN
2 RxD
3 TxD
5 GND
SSP
9-pin Plug9-pin Socket Connector
RxD_OUT 2
3
5
TxD_OUT
GND_OUT
2 TxD_IN
3 RxD_IN
5 GND_IN
9-pin Plug 9-pin Socket Connector
SSP
OUT
IN
RS 232
RS 232
PC/Controller
SSP
IN
RS 232
COM1/COM2
IN OUT
IN OUT
IN OUT
IN OUT
Accessory:
RS 232 Bus Cable, 0.4 meters
Accessory: RS 232 Bus Cable, 2 meters (for example)