Graphtec GL840-M/GL840-WV Isolated/Universal input, Standalone Multi-Chanel Datalogger
Graphtec GL840-M/GL840-WV Isolated/Universal input, Standalone Multi-Chanel Datalogger
Suitable for stacked High Voltage Battery Application, or High-Precision Temperature Measurement.


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 100V | 20mV to 100V |
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), JPt100 (JIS), Pt1000 (IEC751) | ||
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 the temperature levels and thermocouple types.
The following shows how a standard configuration is expanded to more than 40 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) |
N/A | 1 pc | 1 pc | 1 pc |
Terminal base (B-566) | N/A | 2 sets | 5 sets | 10 sets |
Input terminal (B-564 or B-565 ) |
N/A | 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.
Maximum sampling interval of up to 10ms
Provides faster sampling rates for voltage measurements. You are able to achieve up to 10ms sampling speed when limiting the number of channels in use.
Supports large-size SD memort card for reliable long term measurement
New GL840 series carries two SD memory card slots for storage device. The SDHC type SD memory card is supported up to 32GB. 4GB SD memory card comes as a standard accessory installed in the first slot.
the captured data can be stored in GBD(Graphtec binary data) or CSV file format.
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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) |
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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.
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Hot-swapping the SD memory card
SD card can be replaced during data capturing when the sampling interval is 100ms or slower.
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Graphtec GL840-M/GL840-WV Isolated/Universal input, Standalone Multi-Chanel Datalogger | |
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Graphtec GL840M (60Vp-p) Thermocouple/Voltage Logger Withstands voltage of 350 Vp-p (1 min.) |
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Graphtec GL840WV (300Vp-p) High Voltage Logger Withstands voltage of 2300 Vp-p (1 min.) |