Measurements Using The Guard Function; Measurement Accuracy; Option Handler (Sorter) Interface Ho118 For Component Sorting (25 P. Interface); Remote Control - Hameg HM8118 Handbuch

Range Source impedance
25 Ω
1
25 Ω
2
400 Ω
3
4 6,4 kΩ
5 100 kΩ
6 100 kΩ

Measurements using the GUARD function

If the GUARD function is selected the outer BNC contacts
... 23 will be connected to an internal generator which feeds
them with a replica of the measuring voltage thus eliminating
the capacitance of the cables connected which would cause
erroneous capacitance measurements. The driving capability
of the generator is, of course limited, hence with very high ca-
pacitances and simultaneously high frequencies the effect will
be limited. The following settings are available:
OFF: Guarding off, the outer contacts of the BNC connectors
are connected to measuring ground.
DRIVE: Guarding is on, the outer BNC contacts are connected
to the guard voltage generator. LOW DRIVE potential.
AUTO: At frequencies < 100 kHz and in ranges 1 to 4 the outer
contacts are connected to measurement ground. At frequencies
> 100 kHz and in ranges 5 to 6 guarding will be on.

Measurement accuracy

The measurement error remains < ± 0.05 % with resistance R,
capacitance C and inductance L measurements. The measure-
ment error with quality factor measurements is DQ ± 0,0001.
Option Handler (Sorter) Interface HO118 for compo-
nent sorting (25 p. interface)
A handler interface is handy in production environments e.g. for
incoming inspection component checks or selection to limits.
The handler interface has control ouputs in order to deliver
information about the sorting of the components, also in order
to interrogate the status of the measuring bridge. There is a
trigger input for starting the measurements.
The interface contains 8 control lines for bins, a bin for scrap,
a general bin for scrap, active measurement and sorter bin
data. The control lines are open-collector outputs and take up
to 40 V. The trigger input reacts to TTL level signals and their
negative slope, it is protected up to ± 15 V.
Impedance of the
component
3 Ω
10 μΩ to
3 Ω to 100 Ω
100 Ω
to 1.6kΩ
1,6 kΩ to 25 kΩ
25 kΩ to 2 MΩ
2 MΩ to 100 MΩ
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Remote Control

Interfaces for remote control and data transfer.

1. RS-232 interface (9pin subD connector)

The RS-232 interface uses a standard 9pin subD connector.
This bidirectional interface allows the exchange of measure-
ment parameters between an external device (DTE, e.g. a pc
with suitable measurement software) and the HM8118 (DCE).
Also commands can be transmitted and data read. The chapter
„Reference listing of commands" contains a survey of available
commands. A direct link between the serial port of a pc and the
instrument's RS-232 interface may be established by a standard
9 conductor shielded cable (1:1); only shielded cables of < 3 m
may be used. The functions of the pins are as follows:
2 Tx transmit data from the HM8118 to the external device
3 Rx receive data from the external device
7 CTS (clear to send) ready to transmit
8 RTS (request to send) ready to receive
5 GND ground connection; this pin is directly connected
through the instrument to the mains safety conductor
(Protection Class I).
The maximum voltage swing at the terminals Tx, Rx, CTS, RTS
is +- 12 V.
The standard RS-232 parameters are:
N-8-2 (no parity, 8 data bits, 1 stop bit, an optional software
data fl ow control bit XON/OFF.
The Baud rate of the RS-232 interface can be set by pressing
the SELECT button, choosing the menu SYST and BAUDS. The
following Baud rates are available: 1200, 2400, 4800, 9600,
19200.

2. USB

The interface is equipped with a Type A USB female connector.
For direct connection with a host controller or an indirect con-
nection via a USB hub, a USB cable is required, equipped with
Type B male connector one end and a Type A male connector
at the other.
Type A Type B

USB-Driver Installation

Connecting the instrument with the PC for the fi rst time, the
operating system answers "Found New Hardware". In addition
the "Found New Hardware Wizard" is displayed.
The USB Driver is located on the CD included in delivery and
as a ZIP-archive in download area on our website www.hameg.
com.
R e m o t e C o n t r o l
Subject to change without notice
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