- Three external light sensor connectors for fast setup
- Two additional current channels, four voltage channels, one pulse counting channel and several regulated and unregulated voltage supplies
- Easy-to-use internal software with setup macro libraries to simplify sensor configuration
- Alphanumeric keypad speeds entry of remarks for data identification
- Simplified programming can be done via windows software program
Simplified Data Logging
Operating the LI-1400 is easy. All functions are selectable from short lists using cursor keys. Commonly used functions like printing and memory management are assigned to a function list on a dedicated key for quick access. Other important functions like instrument setup and data display are also assigned to dedicated keys.
Channel setup is simplified by the use of log routines that eliminate entering repetitive information. The LI-1400's log routines allow you to enter the logging period, start/stop times and other information in one place, and then apply that log routine to as many channels as required.
Each channel can be individually configured to collect data for logging periods as short as 1 second or as long as 24 hours. Sampling intervals within each logging period are selectable from 1 second to one hour.
For each logging period, data can be integrated or averaged. Alternatively, an instantaneous point reading can be taken at the end of each period. The maximum and minimum readings within the logging period and the time of their occurrence can also be stored.
Math Functions and Channels
The logging and calculation capabilities of the LI-1400 are extended by nine math channels. Channel setup includes choosing from a list of math functions that can be applied to sensor inputs. In addition to sensor input scaling or linearization, several powerful calculations can be performed using math functions.
The LI-1400 uses an autoranging, trans-impedance, chopper stabilized amplifier for high resolution (8 picoamp), high accuracy measurements of LI-COR radiation sensors and other sensors with a current output. The high gain amplifier and unique circuit topology gives an extremely low input impedance.
Highly accurate, single-ended voltage measurements are achieved using a precision instrumentation amplifier. Voltage output transducers with low or high output impedance are accurately measured because of very high amplifier input impedance.
The LI-1400 has unrivaled resolution for LI-COR radiation sensors. Current resolution down to 8 picoamps is available through three sealed BNC connectors and two additional channels on the 1400-301 Terminal Block.
The LI-1400 can measure current up to ± 250 microamps with very high resolution.
1400-301 Standard Terminal Block
Four single-ended voltage channels (± 2.5 VDC) provide high input impedance for measuring a wide range of sensors, including LI-COR temperature sensors and humidity sensors. Voltage measurements require the 1400-301 Terminal Block.
The LI-1400 has one pulse counting channel for logging total rainfall from a Tipping Bucket Rain Gauge. The counter channel can be accessed through the 1400-301 Terminal Block.
The LI-1400's rugged, splash-resistant case protects it from exposure to the environment. Operating temperatures are from -25 to 55 °C.
The LI-1400 is powered by four "AA" batteries which provide over 60 hours of hand-held, instantaneous operation as a meter. For remote logging applications, the 1400-402 external "D" cell battery pack provides over a year of data logging operation from six batteries.
The LI-1400 has 96K bytes RAM for data storage. The storage capacity is dependent on the software configuration.
Table 1. Storage Capacity Examples
|Setup Description||Time Until Memory Full||Bytes
|2 channels, 1 hr periods||with no max/min||208 days||432|
|with max/min (each channel)||110 days||816|
|Daily integration and hourly means from a radiation sensor; hourly means of humidity and temperature, daily rainfall||with no max/min||141 days||638|
|with max/min (all channels except integral)||64 days||1406|
|9 channels, 1 hr periods and 9 math channels, 1 hr periods||with no max/min||45 days||1968|
|with max/min (all channels)||16 days||5424|
Windows® communication software is included for:
- Rapid binary data transfer
- ASCII data transfer
- Datalogger configuration changes from the computer
Stored data can also be transferred to PC-compatible or Macintosh® computers using any terminal program. The LI-1400 data are formatted for easy import into widely used spreadsheet and database software.
Data can be automatically output via the RS-232 port after every logging period. When using short logging periods, this feature allows data capture by a computer with large storage capacity.