Datalogger Discovery Newsletters
No.2 April 26, 2016

This second installment of our monthly newsletter will focus on the third generation GL840—with its high performance and multi-channel measurement capabilities for handy, portable datalogging. The ability to monitor up to 300Vp-p with 2300 Vrms withstand DC measurement on the GL840-WV protects this instrument from any high voltage leaks. Wireless monitoring is also now available with the GL840s, and the new Pelican case will further protect your investments to its fullest potential.

wlan wireless dataloggingwlan wireless dataloggers

(Optional B-568 WLAN and Pelican protective case shown.)


This month, we cover the basic features of the GL840-M multi-input and the GL840-WV withstand-voltage model dataloggers. With these two new models, focus is on the general 20-channel temperature/voltage input datalogger and the voltage-withstand datalogger with higher accuracy, higher voltage input capability and glitch protection. GL840-M is ideal for multichannel measurements of linear voltage output (or 4-20mA current loops), thermocouples, and RTDs. GL840-WV will support requirements for high precision measurement of temperature and voltage as well as high voltage—such as battery cell voltage monitoring and measurement.

multichannel withstand high voltage datalogger

Expandability up to 200 channels

The key capability of the GL840 is on its expandability of up to 200-channel input measurements using its expansion terminal blocks. The basic configuration for the expansion kit will require an extension cable, extension terminal base, and the 20-channel extension terminal block. The GL840 series, on both the multi-input model and the withstand model, now provides the ability to connect each terminal base in combination with the terminal block—with the extension cable in addition to the traditional method of daisy chaining terminal blocks to each other.

Q: How do you configure the expansion blocks on the GL840 series?

    A: There are several components that are required to set up the expansion terminal blocks for the GL840 models. Each model will require one expansion cable to connect the first expansion terminal base which would initially connect the first 20 channel block with the main instrument. The original 20 channel block from the main unit will snap out of the body, and the corresponding 20 channel block will then snap on to the first extension terminal base. This cable can now be either 1.6 ft (50cm) or 6.5 ft (2 meter) long. Thereafter, depending upon how many channels you will need to configure, each corresponding extension terminal base (B-566) will add additional 20 channel blocks either via a cable or directly daisy-chaining on to each other. Either the B-564 20 channel terminal block for the GL840-M or the B-565 20 channel terminal block for the withstand model GL840-WV can be used as the terminal block mixed together on the series of channel blocks.

          *Used for both B-564 and B-565

Q: What are the key advantages for using the GL840-WV, and which applications do you recommend for the GL840-WV?

    A: The key advantage of the GL840-WV model is in the precision accuracy of its measurement and its capability to withstand higher voltage requirements. Voltage accuracy on DC input is ±0.05% of full scale (+10µV), and average accuracy for thermocouple measurement increases by anywhere from 0.5˚C to 1.7˚C depending upon the range and the type of your typical thermocouple wires. (please review the specification below to review your specified range) The other key advantage is in its ability to withstand up to 300Vp-p channel-to-ground and 600Vp-p in between channels with 2300Vrms AC (for 1 minute) channel-to-ground. This provides the monitoring ability to connect series stacked cells for power batteries up to 300V with no issues as a viable monitoring tool for battery efficiency and performance. Solar panel networks and other power grid networks can now be monitored with this cost-efficient monitoring tool.


screen based standalone wlan dataloggers“We found Graphtec Loggers to be very intuitive—with the ability to monitor and see that the recording is all going fine.”
– Engineer, Whirlpool


Key Features

blue bullet Review Your Data While Recording is ON

GL840 series now allows you to review your data while the recording goes on in the background.


blue bullet Protect Your Investment With GL840-WV

The ability to withstand up to 2300Vrms AC signal protects the GL840-WV main body from high voltage glitch wires as well as electromagnetic interferences.


standalone wireless wlan data acquisition

blue bullet Connect GL100 GS Sensors to GL840 Series

Direct connection for GS sensors from the GL100 series
to the GL840 main body allows additional sensor capabilities
for light illumincance, vibration, UV, CO2, and AC current
(50A, 100A, 200A) datalogging.




Wireless and Non-wireless Access To GL100 Sensors

Five GL100-WL wireless compact dataloggers can also be monitored real-time using the wireless feature to the GL840s using the main GL840 as the access point hub. The data from the GL100-WL can be displayed real time on the displays of the GL840 and data will be recorded in additional channels for CSV or GBD file formats available on the GL840.

screen based standalone dataloggers     WLAN Access Station Datalogging


Product Fact Sheet

GL840-M / GL840-WV 20-channel Datalogger Key Values

  • High performance measurement
  • Up to 200 channe monitoring for complex qualification systems
  • Direct Excel recording (on .csv file format)
  • High isolated mechanism with ability to select input per channel
  • Measurement focused APS software
gl840 screen based datalogger specifications

gl840 data logger accessories
gl840 datalogger accessories


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