Greisinger GMH 3750 User guide

H49.0.02.6B-06

as of Version 1.8

Operating Manual Precision Thermometer

Pt100 4-Wire

GMH 3750

GREISINGER electronic GmbH

D - 93128 Regenstauf, Hans-Sachs-Straße 26

Phone: +49 9402 / 9383-0, Fax: +49 9402 / 9383-33, eMail: [e-mail]

H49.0.02.6C-06 Operating Manual GMH 3750 Page 2 of 16

_____________________________________________________ _______________________________________________________________________________

Contents

1 INTENDED USE .........................................................................................................................................3

2 GENERAL ADVICE...................................................................................................................................3

3 SAFETY INSTRUCTIONS ........................................................................................................................3

4 OPERATING AND MAINTENANCE ......................................................................................................4

5 CONNECTIONS..........................................................................................................................................4

6 DISPLAY- AND BUTTON ELEMENTS..................................................................................................5

7 START OF OPERATION ..........................................................................................................................5

8 DEVICE CONFIGURATION ....................................................................................................................6

9 SPECIAL FUNCTIONS..............................................................................................................................8

9.1 DISPLAY RESOLUTION ..............................................................................................................................8

9.2 USER SENSOR CURVE ('LIN USER')..........................................................................................................8

9.3 ZERO DISPLACEMENT ('OFFSET') ..............................................................................................................8

9.4 SCALE CORRECTION ('SCALE')..................................................................................................................8

9.5 AVERAGE FILTER („T.AUG“) ...................................................................................................................9

9.6 OUTPUT („OUT“).....................................................................................................................................9

9.7 ALARM („AL.“)......................................................................................................................................10

9.8 REAL TIME CLOCK („CLOC“) ...............................................................................................................10

10 PROBE CONNECTION........................................................................................................................11

11 CALIBRATION SERVICES ................................................................................................................11

12 OPERATION OF LOGGER.................................................................................................................12

12.1 STORING SINGLE MEASUREMENTS („FUNC-STOR“) ...............................................................................12

12.2 AUTOMATIC RECORDING WITH SELECTABLE LOGGER CYCLE TIME „FUNC CYCL“..............................13

13 SOME BASICS OF PRECISION TEMPERATURE MEASURING ...............................................14

14 FAULT AND SYSTEM MESSAGES...................................................................................................15

15 DISPOSAL NOTES ...............................................................................................................................15

16 SPECIFICATION ..................................................................................................................................16

© Copyright 2008 GREISINGER electronic GmbH. All Rights Reserved.

No part of this documentation may without previous written permission of the company
GREISINGER electronic GmbH stored in some form, reproduced, processed,
duplicated or spread become.

H49.0.02.6C-06 Operating Manual GMH 3750 Page 3 of 16

_____________________________________________________ _______________________________________________________________________________

1 Intended Use

The GMH 3750 is a precision thermometer for the measurement of the temperature with
exchangeable 4-wire Pt100 temperature sensors. With high resolution and precision temperature
values can be measured from -200 to 850 °C.
The device is to be protected against wetness and soiling and has to be stored and operated only
within the permissible environmental conditions and connection data (see “Specification”).

2 General Advice

Read through this document attentively and make yourself familiar to the operation of the device
before you use it. Keep this document in a ready-to-hand way in order to be able to look up in the
case of doubt.

3 Safety Instructions

This device has been designed and tested in accordance to the safety regulations for electronic
devices. However, its trouble-free operation and reliability cannot be guaranteed unless the
standard safety measures and special safety advises given in this manual will be adhered to when
using it.

1. Trouble-free operation and reliability of the device can only be guaranteed if it is not subjected
to any other climatic conditions than those stated under “Specification”.
Transporting the device from a cold to a warm environment condensation may result in a failure
of the function. In such a case make sure the device temperature has adjusted to the ambient
temperature before trying a new start-up.

2. The circuitry has to be designed most carefully, especially if the device should be connected to
other devices. Internal connection in third party devices (e.g. connection GND and earth) may
result in not-permissible voltages impairing or destroying the device or another device
connected.

3. Warning: Operating the device with a defective mains power supply (e.g. short circuit from
mains voltage to output voltage) may result in hazardous voltages at the device (e.g. at sensor
socket)

4. Whenever there may be a risk whatsoever involved in running it, the device has to be
switched off immediately and to be marked accordingly to avoid re-starting. Operator safety may
be a risk if:

• there is visible damage to the device

• the device is not working as specified

• the device has been stored under unsuitable conditions for a longer time

In case of doubt, please return device to manufacturer for repair or maintenance.

5.

Warning: Do not use these product as safety or emergency stop device, or in any other
application where failure of the product could result in personal injury or material damage.
Failure to comply with these instructions could result in death or serious injury and material
damage.

H49.0.02.6C-06 Operating Manual GMH 3750 Page 4 of 16

_____________________________________________________ _______________________________________________________________________________

4 Operating and Maintenance

• Battery Operation
The battery has been used up and needs to be replaced, if „bAt“ are shown in lower display.
The device will, however, continue operating correctly for a certain time.
The battery has been completely used up, if ´bAt´ is shown in the upper display.
The battery has to be taken out, when storing device above 50°C.

Hint: We recommend to remove the battery if device is not used for a longer period of time!

• Mains Operation

Attention: When using a power supply unit please note that operating voltage has to be 10.5 to
12 V DC. Do not apply overvoltage!! Simple 12V-power supplies often have excessive no-load
voltage. We, therefore, recommend using regulated voltage power supplies. Trouble-free
operation is guaranteed by our power supply GNG10/3000.
Prior to connecting the plug power supply with the mains supply make sure that the operating
voltage stated at the power supply is identical to the mains voltage.

• Treat device and probes carefully. Use only in accordance with above specification. (do not

throw, hit against etc.). Protect plugs and sockets from soiling.

• To disconnect sensor plug do not pull at the cable but at the plug.

• When connecting the probe the plug will slide in smoothly if plug is entered correctly.

Selection of Output-Mode: The output can be used as serial interface or as analogue output. This
choice has to be done in the configuration menu.

5 Connections

1 Probe connection: 4 pole Mini-DIN-Socket, for Pt100 4-wire probes (see also chapter 10)
2 Output: 3-pole stereo phone socket Ø3mm

Operation as interface: Connection to optically isolated interface adapter (accessory: USB 3100,
GRS 3100, ..)
Operation as analogue output: Connection via suitable 2pole cable.
Attention: The output mode has to be configured (see chapters 8, 9.6) and influences battery life!

The mains socket is located at the left side of the instrument

H49.0.02.6C-06 Operating Manual GMH 3750 Page 5 of 16

_____________________________________________________ _______________________________________________________________________________

6 Display- and Button Elements

a

) Display Elements

1 Main Display: Currently measured temperature
2 Auxiliary Display: Display of min, max or hold values

Special display elements:

3 Min/Max/Hold: shows if a min., max. or hold value is displayed in

the auxiliary display

4 „Offset“ arrow: indicates that zero point offset is activated

5 „Corr“ arrow: indicates that a scale correction is activated

6 „Logg“ arrow: Shown if logger function is selected,

flashes if cyclic logger is running

7 „Alarm“ arrow: Flashes if alarm is present

b) Pushbuttons and Operation

Key 1:
On/Off

Key 2:

press shortly: maximum measured value will be displayed
press for 2 sec.: the max. value will be deleted

Key 3:

Function only during configuration: Selection of menu-parameter

Key 4:

press (Menu) for 2 sec.: configuration will be activated

Key 5:

press shortly: minimum measured value will be displayed
press for 2 sec.: the min. value will be deleted

Key 6:

Measurement: Hold current measuring value ('HLD' in display) or operation of logger
functions (p.r.t. Chapter 12)

7 Start of Operation

Connecting Temperature probe to the instrument.
Switch instrument on with key 1 „ON OFF”
The device is ready to measure.