midi LOGGER GL840 series

Three types of input system enable to measure various phenomena

Input system 1 : Multifunction analog input ports

Contains a highly isolated input system which ensures that signals are not corrupted by noise from other channels. The GL840's inputs are suitable for combined measurements from voltage, temperature, humidity, logic, and pulse signals.
The standard configuration has 20 analog input channels. It is expandable to 200 channels by adding optional 20 channels extension terminal base unit (B-566) and input terminal units (B-564 or B-565).

Withstand voltage & Accuracy Multi-input type (B-564) Withstand-voltage type (B-565)
Voltage Input voltage range 20 mV to 100 V 20 mV to 100 V
Max. voltage (Input - GND) 60 Vp-p 300 Vp-p
Temp. Thermocouple R, S, B, K, E, T, J, N, W (WRe5-26)
RTD (Resistance Temp. Detector) Pt100 (IEC751), Pt1000 (IEC751), JPt100 (JIS)
Accuracy Voltage ± 0.1% of F.S. ± (0.05% of FS + 10μV)
Temperature* ± 1.55 ºC ± 1.1 ºC

* Accuracy rating for K-type thermocouple at 100˚C includes reference junction compensation. Accuracy varies by temperature levels and thermocouple types.

The following shows how a standard configuration is expanded to more than 40 channels

Configuration for additional channels

Number of channels

20 channels

40 channels

100 channels

200 channels

GL840 unit (GL840-M or GL840-WV)

1 set

1 set

1 set

1 set

Connection cable (B-567-05 or -20)


1 pc

1 pc

1 pc

Terminal base (B-566)


2 sets

5 sets

10 sets

Input terminal (B-564 or B-565 )


1 set

4 sets

9 sets

Offers longer cable for the input terminals

Input terminal blocks can be connected directly (in daisy chain), or using the B-565 cable(s). This allows the input terminals to be placed in separate locations according to the need of the application.

The input terminal unit and the GL840 main body can be extended by using an extended connections cable.

*If the signal is affected by noise, it may be required to use a slower sampling.

Input system 2 : Support digital sensors

Digital sensors and input terminal/adapters for the GL100 connects to the GL840 directly

Input system 3 : 4 channels of Logic/Pulse inputs

Supports 4-channels logic or pulse signal inputs. Pulse mode allows cumulative, instant, or rotational values for industrial measurement capability with speed and flow.

Maximum sampling interval of up to 10ms

Provides faster sampling rates for voltage measurements. Up to 10ms sampling speed is achievable when limiting the number of channels in use.

Sampling Interval

10ms 20ms 50ms 100ms 200ms 500ms 1s 2s

Number of channel

1 2 5 10 20 50 100 200




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Built-in 4GB Flash memory with SD card support

The new GL series enables reliable long term measurment with its built-in 4GB flash memory and SD card slot for external storage devices. The SD card slot supports an SDHC memory card of up to 32GB.

The captured data can be stored in GBD (Graphtec binary data) or CSV file format.

Capturing time* (when all 20 analog channels are being used with Logic/Pulse inputs turned off.)


10ms 50ms 100ms 200ms 500ms 1s 10s

GBD format

31 days 77 days 95 days 108 days 270 days Over 365 Over 365

CSV format

3 days 11 days 16 days 21 days 54 days 109 days Over 365

*Figures are approximate. File size of captured data is 2GB in GBD or CSV file format on this chart.

Sampling interval is limited by the number of channels in use. (10ms:1ch, 50ms:5ch, 100ms:10ch)

Limited sampling speed is available when digital sensors and GL100-WL are used as a remote monitoring device.

Ring capture function

The most recent data is saved when the memory is configured in ring memory mode. (Number of capturing data is 1000 to 2000000 points)

Relay capture function

Data is continuously saved to multiple files up to 2GB without losing any data until capturing is stopped when the memory is configured in the relay mode.

Hot-swapping the SD memory card

SD card can be replaced during data capturing when the sampling interval is 100ms or slower.

Back up recording data

The data file can be created periodically for purpose of backing up data while recording it, and the file is automatically transferred to another storage device on the unit or FTP server on the network.
Back up recording data Backup interval: 1, 2, 6, 12, 24 hour(s)
Backup file destination: SD memory card or FTP server
Data file format: GBD (binary) or CSV (text)
• Available sampling speed is the 100 ms or slower when using the CSV format.
• When the RING mode or external pulse synchronization sampling is selected for recording, the backup function is not available.
• The storage device specified as the recording destination of the measurement data can not be set as the transfer destination of the backup file.
• When backup is enabled and data file format is specified with CSV format, SD memory card exchange (hot-swapping) and RELAY recording are not available.

Data file verification

Back up recording data It is a function to check the integrity of the data file when replaying the data file. It compares check-sum generated from the data file and recorded check-sum. When two check-sums do not match, the data file may be corrupted or has been changed by someone. The check-sum code is recorded into the file when data file is created by the GL unit.
* Check-sum code is added to normal data recording file and also file created for backup, ring or relay recording. Adding check-sum is available for data files created in GBD format.When the recorded data file is converted and saved using GL100_240_840-APS or GL-Connection software, the check-sum code will not match.
* This function is available with firmware version 1.43 or rater.

Useful functions

Displays the data by a bar chart (in firmware ver.1.10 or later)

The integrated data that is measured by the digital sensors can be displayed by a bar chart in the GL840 series.



Available GS sensors Measurement Unit
GS-TH (Temp/Humidity) sensor Integrated temperature ℃h
GS-DPA-AC adapter with GS-Acxxx sensor (AC current/power) Integrated power kWh
GS-LXUV (Illuminance/UV) sensor Integrated illuminance lxh or klxh
Integrated UV mW/cm2h

Alarm output function

Alarm signals can be placed using the four channel alarm output ports based on set conditions for each channel.
* Optional cable (B-513) is required.

USB drive mode

USB drive mode function enables data to be transferred to the PC from GL840 by drag & drop feature.

Navigation function

Simple to use navigation screen allows setting operation for measurement and wireless LAN adapter.

Large easy-to-read 7-inch wide color LCD

Monitoring data can be displayed in waveform or digital form. Parameter settings can be displayed on the screen.

3 Types of Power Source

Choose from AC power supply, DC supply* or the rechargeable battery pack.*
* Optional accessories (B-514 or B-569) are required.

Networking features

Various functions are available using a network.
Web & FTP server function, FTP client function, NTP client function

Cover (B-578)

Protect the main body from cosmetic damages and minor impacts.
* The cover is not to protect from hard impact.

Storage case (B-581)

Portable case to store GL840 and signal input cables for easy handling.
* The case is not to protect from hard impact.