User Manual
GMC-I Messtechnik GmbH 19
12.6 Transmission Mode Operation with RS 232 Interface
The METRA HIT27 is equipped with an bidirectional infrared
interface for the transmission of measurement data to a PC.
Data are transferred optically through the instrument housing
by means of infrared light to an interface adapter (accessory
USB-HIT), which is attached to the instrument. The adapter’s
USB-HIT-interface allows for the establishment of a
connection to the PC via an interface cable.
The driver to be installed assigns a virtual COM interface to
the instrument. It is not possible to set up a multi-channel
system with this adapter.
Beyond this, commands and parameters can be transmitted
from the PC to the instrument as well. The following functions
can be executed:
• Configuration and read-out of measuring parameters
• Measuring function and measuring range selection
• Start measurements
• Read out measured values
Activating the Interface
The interface is switched on manually as described below for
transmission mode operation. The instrument continuously
transmits measurement data to the PC via the interface
adapter in this operating mode. The interface is activated
automatically by the PC for receiving operation (i.e. the
instrument receives data from the PC).
Starting Transmission with Menu Functions
InFO SEnd StArt
The symbol blinks at the display in order to indicate
interface operation.
Automatic Activation and Deactivation of the Transmission Mode
If the sampling rate is 20 s or longer, the display is switched
off automatically between samples in order to prolong
storage battery or battery service life.
Exception: continuous operation
As soon as an event occurs, the display is automatically
switched back on.
Configuring Interface Parameters
Addr – Address
If several instruments are connected to the PC via interface
adapters, an unique address must be assigned to each
device. Address 1 should be used for the first device,
address 2 for the second etc. If only one multimeter is
utilized, an address between 1 and 14 should be used.
Address 15 is not used for addressing, i.e. the device with
address 15 always responds, regardless of the actual
address.