Default welcome msg!

CB25 Terminal Board

Provides screw terminal connections for the LabJack U12's 16 extra digital I/O. A screwdriver and DB25 cable are included. For the LabJack U12 only.

Details

Details

Datasheet Revision 1.02, 2/4/2002

The CB25 Provides screw terminal connections, with short-circuit/overvoltage protection, for the extra 16 digital I/O on the LabJack U12.

The green LED on the CB25 is directly powered by the +5V supply, so it should be lit whenever the CB25 is connected to an active LabJack U12.

D0-D15 – These are connections to the 16 lines of digital I/O. Each has a 1.5kΩ series resistor (R0-R15) for short-circuit/overvoltage protection, and a jumper (J0-J15) to short that resistor. In general, the jumpers will not be installed unless you are using a particular line to output more than 1 mA. See the specifications section of the LabJack U12 User’s Guide for more information on the D lines.

Short-Circuit/Overvoltage Protection: The LabJack U12 has diodes from each D line to each power rail. These diodes clamp the voltage seen by the LabJack to about 5.7 volts maximum and -0.7 volts minimum, but external resistors are required to limit the current to 25 mA (200 mA total for all 16 lines). The CB25 provides 1.5kΩ resistors for this purpose. Taking 1.5kΩ * 25 mA, we get a maximum voltage drop of 37.5 volts so the maximum safe voltage that can be handled by each D line is about 37.5 + 5.7 = 43.2 volts (the minimum safe voltage is about -38.2 volts). Note, however, that the power dissipated by the resistor in this situation is ((0.025)^2)*1500 = 0.94 watts. Since these are ¼ watt resistors you will not be able to block this maximum voltage continuously. The maximum continuous voltage drop is about (0.25 * 1500)^0.5 = 19.4 volts so the maximum safe continuous voltage that can be handled by each D line is about 19.4 + 5.7 = 25 volts (the minimum safe continuous voltage is about -20 volts).

+5V – These are the same as the +5V connection on the LabJack U12. They are a 5 volt source (output), so do not connect another power source to these terminals.

GND – These are the same as the GND connection on the LabJack U12.


  Product Comparison

U12 U3-LV U3-HV U6 U6-Pro UE9 UE9-Pro T7 T7-Pro
AIN Voltage ±10V 0-2.4V ±10V [1] ±10V ±10V ±5V ±5V ±10V ±10V
Analog Inputs 8 16 16 14 14 14 14 14 14
Effective Resolution [2] 12 bit 12 bit 12 bit 16 bit 22 bit 12 bit 20 bit 16 bit 22 bit
Digital I/O 20 20 16 20 20 23 23 23 23
Logic Level 5V 3.3V 3.3V 3.3V 3.3V 3.3V 3.3V 3.3V 3.3V
Analog Outputs 2 2 2 2 2 2 2 2 2
Counters 1 Up to 2 Up to 2 Up to 2 Up to 2 Up to 2 Up to 2 Up to 10 Up to 10
USB Yes Yes Yes Yes Yes Yes Yes Yes Yes
LJTick Compatible No Yes Yes Yes Yes Yes Yes Yes Yes
Internal Temp Sensor No Yes Yes Yes Yes Yes
Yes
Yes Yes
Thermocouple Ready [3] No No No Yes Yes No Yes Yes Yes
Ethernet No No No No No Yes Yes Yes Yes
Scripting No No No No No No No Yes Yes
Wireless No No No No No No No No Yes
Real-time Clock No No No No No No No No Yes
[1] Can be configured for -10V to +20V range.
[2] According to actual measured data, see related Noise and Resolution (App Note)
[3] If not thermocouple ready, can purchase an amplifier like the LJTick-InAmp, see related Thermocouples (App Note)