Diode Test; Temperature Measurements; Decibel Measurements; Equipment Remote Control - Hameg HM 8012 Manual

preferable to remove, if necessary, any
components connected to the semiconductor for
precise results. It is possible to measure voltages
up to 5 V. The maximum voltage that the
equipment will supply is 10 V in an open circuit.
If the cathode of the DUT is connected to the
ground (COM-terminal), the diode operates in its
conducting mode. If the anode of the DUT is
connected to ground, the diode operates in its
reverse mode. For measurements on Zener-
diodes, the anode of the device should be
connected to ground. Take care when making
measurements on sensitive circuits. The current
supplied by HM8012 is 1 mA constant for this
function. All keys except s, t and HOLD/OFFSET
are inactive for this function.

Temperature measurements

Choose the temperature measurement function
(°C or °F) using s or t key. The temperature probe
is connected between the COM terminal and the
V/Ω/T°/dB terminal. The temperature probe is
connected between the COM terminal and the
V/Ω/T°/dB terminal.
Temperature measurement
temperature probe type Pt100 as per standard
EN60751. The instrument is designed for the
HZ812 probe. The use of another probe is
possible but can generate additional errors due
to a different link cable resistance. All keys except
s, t and HOLD/OFFSET are inactive for this
function.
After the instrument has been turned-on, the line
resistance value of the temperature probe HZ812
is automatically compensated.
On starting, simultaneously pressing BEEP and
OFFSET will eliminate probe cable resistance
compensation (zero value).
compensation can be carried out by setting the
probe to a temperature of 0°C and using the
OFFSET function.
Note: Measurement of the temperature probe Note: Note:
Note: Note:
line resistance should be made on the same
instrument used for temperature measurements.
Only this procedure guarantees the specified
measurement error.

Decibel measurements

Choose the decibel measurement function using
s or t key. For decibel measurements, the
unknown input voltage is connected between the
COM terminal and the V/Ω/T°/dB terminal.
The HM8012 is used for DC or AC voltage
measurements in decibels. The 0dB reference
is defined for 1mW power in a 600Ω load., i.e. a
voltage of 0.7746V. The scale extends from -
78dBm to 59.8dBm.
In a 50Ω-system, the reference voltage for 1mW
30
power is 0.2236V. In a 75Ω-system, the reference
voltage for 1mW power is 0.2739V.
If decibel measurements are made on a 50W-
system, add 10.8dB to the displayed value. If
decibel measurements are made on a 75W-
system, add 9dB to the displayed value. The
mathematical relationship is as follows:
R= Reference resistance in W ; P
Sign consideration: A displayed value of –12dB
is equivalent in 50Ω to: -12dB +10.8dB = -1.2dB

Equipment remote control

HM8012 includes a front panel connector for
controlling the equipment by means of a point-
to-point serial link. There are three wires used :
RxD (Receive Data), TxD (Transmit data), SGnd
(Signal Ground). The signal voltage levels must
comply with the following levels (+/- 15 V max.,
+/- 3 V min.).
The link is of the bi-directional asynchronous type
requires a
with a fixed configuration: 4800 Baud, 8 bits, no
parity, one stop bit. The synchronization protocol
is XON/XOFF (half duplex) and is also fixed.
Each control must have two ASCII code
characters followed by character 13 (symbolized
as <CR> in ASCII) or two characters 13 and 10
(symbolized as <CR> <LF> in ASCII), while the
<LF> character is ignored during reception.
The instrument internal buffer includes only three
characters, and there is no way of sending more
than one command at a time. On reception of
terminator <CR>, the equipment sends the
character 19 (<DC3> ASCII) to indicate that the
dialogue is suspended. As soon as it is possible
In all cases,
to resume dialogue, the instrument sends
character 17 (<DC1> ASCII).
The commands are divided into six groups.

Function commands

These commands are used for choosing another
magnitude to be measured and corresponding to
the choice of FUNCTION key on the front panel.
VO<CR>
AM<CR>
MA<CR>
OH<CR>
DI<CR>
TC<CR>
TF<CR>
DB<CR>
For these commands, there is no error recovery
provided for because it is normally possible to
=1mΩ; V
0
voltage measurement (VOLT)
current measurement (A)
current measurement (mA)
resistance measurement

diode test

temperature measurement in °C
temperature measurement in °F
measurement in dB.
Subject change without notice
in V
0