E035 - T24 Telemetry System Frequently Asked Questions
T24 General System
Q: How reliable are the readings?
A: Due to the digital nature of the T24 system, when a reading is received by any device it is guaranteed not to have been distorted over the RF transmission channel.
Q: What software is provided with the T24 devices?
A: All devices are supported by the T24 Toolkit that allows users to configure all devices from the T24 range as well as view and log data from acquisition modules in range. This is available for download along with a pdf manual.
Q: How many devices can operate on one radio channel?
A: Many devices can operate on the same radio channel depending on the sample rate of the acquisition modules present in the system. There are 16 channels available with each one capable of supporting up to 200 data packets per second.
Q: Can PC software gather data from many devices?
A: Yes, free software is available for logging up to 24 inputs to one base station, in addition the open COM driver can be used to gather data through customer's own PC software to applications in Visual Basic which in turn has been used to integrate the T24 system with Lab View.
Q: What Frequency does the system operate on?
A: Licence free world wide 2.4GHz, although this frequency is used by other equipment the T24 range has been tested with Bluetooth, Zigbee and WiFi devices with out conflicts.
Q: What limits the RF range of the devices?
A: Any metal surface will reflect 2.4 GHz radio waves so large metal objects will affect signal propagation. Non-metal objects also have an effect; some plastics can be particularly bad.
Q: What test conditions were used for the transmission distances in the data-sheets?
A: The loadcell acquisition module was mounted 3 metres above the ground in a free field site with a clear line of sight to a T24-HS handheld display held at chest height.
Q: Is the system point to point?
A: Yes, however the modules may also operate in many to one (such as multiple data acquisition modules communicating with a base station) and one to many (such as a data acquisition module supplying data to multiple handhelds and displays).
Q: What is the communication protocol?
A: Proprietary protocol based on an 804.15.4 chip. This allows the T24 range to co-exist with Bluetooth, Zigbee and WiFi devices without conflicts.
T24 Loadcell Acquisition Module
Q: What are the sampling rates of the loadcell acquisition module?
A: The T24 standard loadcell acquisition module samples from 0 to 200 updates/sec. The resolution is dependant on the sampling rate.
Q: What is the resolution of the loadcell acquisition modules?
A: The noise free resolution for a sample time of 10 milli-seconds better than 15 bits (1 in 32,768); with increased sample times resolution can be increased to better than 18 bits (1 in 262,141).
Q: Is the length of the cable between the loadcell and the loadcell acquisition module limited?
A: Yes. The maximum length of the cable should be 3m.
Q: Does the loadcell acquisition module require an external antenna?
A: No. The standard version has an internal antenna mounted inside the plastic case.
Q: Is the loadcell acquisition module enclosure sealed?
A: Yes. When the loadcell cable is properly fitted into its cable gland the enclosure is sealed to IP67.
T24 Handheld Display
Q: What is the battery life of the handhelds?
A: Approximately 35 hours continuous use with alkaline batteries.
Q: Are they IP rated?
A: Yes to IP67.
Q: What batteries are required?
A: 2 x AA, alkaline, zinc or rechargeable NiCad, NiMH.
T24 Base Station
Q: Once an acquisition module has been configured, will it require regular connections to the base station?
A: No. Once an acquisition module has been configured it will remain stable providing its operating limits are not exceeded.
Q: How many T24 Acquisition modules can be controlled by one USB Base Station at the same time?
A: Acquisition modules are not controlled when providing data, rather data is provided at a user determined rate during configuration set up. The base station can gather data from a number of acquisition modules providing they are on the same channel. The number of modules a single base station can process depends upon the frequency of transmission from the acquisition modules on that channel.
Q: Is the T24-Bsu base station sealed?
A: No it is rated at IP50. It uses a standard USB connector.
Q: Can the USB cable be extended?
A: Yes, up to a maximum of 5m. This limit is set by the USB standard.