Data Communication; Layout Of Commands; Comand Reference - Hameg HM8112-3 Handbuch

D a t a C o m m u n i c a t i o n
Interface parameters RS-232
Settings: No parity bit, 8 data bits, one stop bit, Xon-Xoff
Baudrate: The communication is carried out with 9600 baud
or 19200 baud.
Using an IEEE interface (HO880) the baudrate has to
be set to 9600 baud.
STOP

Data communication

Layout of commands

A command consists of 5 ASCII characters:
1. Character: 0
2. Character: Command category (0, 1, 2 or E)
3. Character: Function between 0 and F
4. Character: Parameter between 0 and F
5. Character: Terminator, either CR or LF
– all commands end with CR or LF
– the character set includes fi gures 0 – 9, characters A – F
and CR, LF
– the characters can be entered as upper case or lower case
letters
– Figures 2, 3 and 4 received after 0 are interpreted as a
control command. After a command has been transmitted
a delay of at least 35 ms must be observed, then the next
command can be sent.
– A transmission of invalid commands is answered with 02D0
in case of wrong length of the command or void command
category, with 02D1 for group 1, with 02D2 for group 2 and
with 02DE for group E. This helps debugging the controller
program. The error message is transmitted immediately
after occurrence.
Notes concerning some commands:
0000...0004 Measurement of DC voltage, ranges 100 mV to
600 V
0010...0014 True RMS with DC
0016...0019 True RMS without DC
02C3...02C5 This message is sent after a change of function
or range
02F0...02F3 Request of the instrument's data
By pressing button „LOCAL" the instrument returns
to manual mode.
HINT
Command reference
Group 0 controls all measurement functions. If a measurement
time > 1s was selected, it will be set to 1 s after any change of
function. A change of range will not affect the measurement time
selected. A change of function or range will, however, always
cause a fresh selection of fi lters.
Function 0 to 5:
This parameter selects the range, autoranging will be disabled.
Parameter 9 (no change) will retain the previous range selec-
tion.
50
Subject to change without notice
Function 1:
Parameters 0 to 4 select DC coupling, 6 to 9 AC coupling.
Function 8:
FREQ VAC requires a valid parameter 1 or 2. During frequency
measurement the voltage measurement will be disabled, hence
also autoranging. The range previously selected in the function
VAC will be retained.
Function B:
Diode test with parameter 9.
Function C:
Continuity test with parameter 6 (R
Functions D and E:
2- or 4-wire-temperature measurements require parameter
3 for PT100 or 5 for PT1000.
Function F:
Temperature measurement with thermocouple, requires pa-
rameter 1 for type J or 2 for type K.
Group 1 controls the measurement functions of the instru-
ment.
Function 0 (Autorange):
– Parameter 0 turns autoranging off.
– Parameter 1 turns autoranging on.
– Parameter 8 selects the next higher range until the highest
is reached.
– Parameter 9 selects the next lower range until the lowest
is reached.
Function 1 (Meas – Time):
– Parameter 1 to 7 select the measurement time from 10
ms to 60 s. The measurement results are available at the
interface with the measurement time chosen.
– Parameter 8 selects the next higher measurement time
until the longest is reached.
– Parameter 9 selets the next lower measurement time until
the shortest is reached.
Function 2 (Filter length) inserts a continuously averaging
fi lter.
– Parameter 0 turns the fi lter off.
– Parameter 1 to 4 select the number of measurement results
averaged (2,4,8,16).
Function 4 (Math Program):
– Parameter 0 turns the math function off. Autoranging is
disabled. If desired autoranging must be turned on by the
command 0101. If the Min/Max function is turned off on the
keyboard autoranging will be automatically chosen.
– Parameters 1 to 3 select one of the math functions OFFSET,
HIGH LIMIT, LOW LIMIT; the last result sent will be auto-
matically taken as the reference value. If the HIGh LIMIT or
LOW LIMIT is reached a continuous beep will be sounded,
the interface will transmit 999999.9.
– Parameters 7 and 8 turns the Min/Max function on, autoran-
ging will be disabled.
Function 6 defi nes the trigger modes.
– Parameter 0 selects autotrigger. This means that each new
result will be automatically transmitted after the measure-
ment time (011X) selected has elapsed.
– Parameter 1 selects single trigger. Each command 0161
triggers just one measurement. Buffer operation and sto-
rage of results will not be affected. Single trigger operation
= 10 Ω).
threshold