Measurement Computing Data Translation DT3034, User Manual

Page: 43 / 178

Chapter 4
42
Screw Terminal Assignments
Screw terminals TB1 to TB56 on the DT740 screw terminal panel correspond to the analog I/O
channels from the DT3034 board. Screw terminals TB57 to TB112 on the DT740 screw terminal
panel correspond to the digital I/O signals from the DT3034 board.
Screw terminals TB37 (+15 V) and TB39 (

15 V) on the DT740 screw terminal panel are
available for low-current signal conditioning applications. The supply on the DT3034 board is
current-limited through a 10

resistor and is specified for a maximum load current of ±3 mA.
Screw terminal TB49 (+5.0 V reference) on the DT740 screw terminal panel is also
current-limited through a 10

resistor and is provided for applications that require a
reference less than 1 mA.
Screw terminal TB112 (+5 V output) on the DT740 screw terminal panel is current-limited
through a series 10

resistor and supports loads up to 100 mA. Note that you must take the
drop (current [I] multiplied by resistance [R]) across the series 10

resistor (1 V at 100 mA)
into consideration.
To provide maximum signal integrity, screw terminals TB35, TB36, and TB51 to TB56 on the
DT740 screw terminal panel have been reserved for external shield connections from the J1
connector. Screw terminals TB105 and TB108 on the DT740 screw terminal panel have been
reserved for external shield connections from the J2 connector. In addition, multiple ground
connections have been allocated for all the digital and clock signals for proper shielding and
current capacity.
Note: If you are connecting a high-speed clock to the DT740, it is recommended that you
connect the return to the adjacent ground screw terminal.
Table 2 lists the screw terminal assignments for connector J1 on the DT740 screw terminal
panel; Table 3 lists the screw terminal assignments for connector J2 on the DT740 screw
terminal panel.