The T8 is in an early release state. Please keep this in mind before ordering. T8 firmware and LJM support are currently in beta. Below are the support resources necessary to use the T8 with LJM. T8 specifications will be added to the T-series datasheet as they are defined.
There are some unique limitations to the T8 when compared to our other devices. Please note these limitations before purchase.
Limitations with Streaming Data Rates:
Sampling any AIN channel on the T8 using stream mode acquisition will return the simultaneously sampled data for all 8 AIN channels. When streaming at 40 kHz with 8 channels of data being read, the T8 will need to transfer 960+ kilobytes per second to avoid a stream buffer overflow. As such, high stream rates are only possible when certain communication requirements are met.
High stream rates cannot be used reliably under any of the following conditions:
- When there is a WiFi hop in the Ethernet network.
- When the connection crosses subnets.
- If there are any other network conditions that can cause long round trip times.
- When using a fully wired Ethernet connection from T8 to a switch and/or a computer.
- When using a USB 3.0 port connected through a powered hub.
The T8 requires more power than previous LabJack devices and is therefore more sensitive to the quality of the power supply and any USB cable used. Inadequate device power can cause issues with T8 operation. When using USB, we recommend powering the T8 with a wall-powered USB hub.
The first ~3 AIN stream samples return invalid data.
It takes ~3 samples for the T8 ADC filter system to start working properly after starting stream. The only recourse is to discard the first couple of readings. We will be investigating ways to reduce the impact of this limitation.
TEMPERATURE#(0:8) registers do not return valid results when sampling at rates faster than 250Hz (register behavior changed in 1.0004):
The 250 Hz limit is a hardware limitation. As of firmware 1.0004, the TEMPERATURE#(0:8) registers will return -9999 when the sampling rate is higher than 250 Hz. This is in contrast to earlier firmware versions, which simply return an incorrect value.
While streaming, temperature and AIN registers cannot be read outside of stream:
This is a limitation of the stream/AIN timing system. The temperature register readings make use of the analog input system. Temperature sensor readings are acquired simultaneously whenever the AIN are sampled and vise-versa. Stream uses the AIN clock system, resulting in erroneous measurements when reading AIN outside of stream. We will most likely resolve this problem by adding better error handling such that trying to read the AIN or temperature registers outside of stream will cause an error.
The T8 analog inputs cannot be read (via command-response) when a stream output operation is in progress.
Planned T8 Functionality
There is some functionality currently available on the T7 that we plan to support on the T8, but that we have not fully implemented yet:
- Triggered Stream
- Externally Clocked Stream
- Dallas 1-Wire Protocol
- Asynchronous Serial Communications
- Software-based Watchdog Timer
- IO_CONFIG_SET_CURRENT_TO_ registers are currently unsupported. IO_CONFIG_SET_DEFAULT_TO_ registers are currently supported.
Currently, trying to read or write power registers such as POWER_ETHERNET will cause an illegal data address error. We have not decided whether this will be a T7 and T4 only register, or if we will implement it for the T8.
We recommend all new customers go through our T8 Quickstart Tutorial.
LJM support for the T8 is currently limited to Windows and Linux x86_64. Please use one of the following installers, no other installers will work with the T8:
Linux x86_64: https://files.labjack.com/installers/T8/labjack_ljm_1.22.0.tar.gz
There are currently no known LJM issues.
T8 firmware is field upgradable. We release new firmware versions as new functionality and bug fixes become available. As new firmware versions are released, they will be made available for download at https://files.labjack.com/firmware/T8.
Latest version: 1.0010
StreamBurst causes the error STREAM_BURST_COMPLETE to be returned if you try to run a regular stream after StreamBurst.
Cannot start stream for some combinations of number of points and rates:
Certain stream scan rates can cause the errors LJME_COULD_NOT_START_STREAM or LJME_RECONNECT_FAILED when starting stream.
Reading the AIN will now throw an error if the AIN system is not properly configured (1.0007).
- Some Digital I/O channels cannot be targeted as a stream address (fixed in 1.0007):
Trying to add some digital I/O channels such as DIO0_EF_READ_A causes an illegal data address error. Note: T8 DIO_EF should be functional outside of stream mode.
- Modified the stream packet sizes to increase the T8 network stack reliability (1.0006)
After streaming, temperature registers can return improper values (fixed in 1.0003).
Ethernet Reconnect (fixed in 1.0002): After closing an Ethernet socket, the T8 will need 30 seconds before that socket can reliably be connected to again. Shorter times will occasionally work. The probability of getting a good connection increases from ~10-20% at 2 seconds to 100% at 30 seconds. This also applies to streaming over Ethernet. Stream data is transmitted over a second TCP socket. LJM will automatically open and close that socket when stream is started and stopped.
AIN_RANGE broken (fixed in 1.000):
Valid AIN results are only obtained when using the ±11V range setting, any other AIN#_RANGE setting results in incorrect measurement values.