User`s guide

130 34980A User’s Guide
4 Low Frequency Multiplexer Switch Modules
34921T Terminal Block
This terminal block with screw- type connections is labeled with the
model number and the abbreviated module name. In addition, space is
available on the label for you to write the slot number.
The 34921T is the only terminal block that provides an isothermal
block with temperature reference for thermocouple measurements.
The temperature sensor is located on the bottom side of the PC board
as shown below. Also shown are two holes that you can use for
connecting an external temperature reference to the terminal block.
NOTE
All modules that connect to the internal DMM are interlock
protected. This means that when an installed module is exposed
(no terminal block or cable is connected), the Analog Bus relays are
open and disconnected from the Analog Buses. See page 120 for
further information.
Te m p er a t u r e
Sensor
34921T (viewed from bottom side)
External
Reference
CAUTION
When wiring the terminal block via cables to the mainframe, make
sure the cables are connected to the correct connector. The cables
provide communication and power to the temperature sensor on
the 34921T terminal block. If cabling is not correct, an error may
occur indicating that the 34921A module is not fully operational.