Service manual

E1343A/44A
Multiplexer
Descriptions
The E1343A 16-Channel High Voltage Relay Multiplexer and the E1344A
16-Channel High Voltage Relay Multiplexer (with thermocouple
compensation) modules consist of an E1343A component assembly (part
number E1343-66201) and a terminal module. Each multiplexer provides
switching (multiplexing) of up to 16 channels (channels 00 to 15). Each
channel has HIGH (H), LOW (L), and GUARD (G) connections. See Figure
4-1 for a block diagram of these modules.
The component assembly is the same for the E1343A and E1344A. The
only difference between the two component assemblies is their module ID
jumper settings. The E1343A uses an E1343-80001 terminal assembly and
the E1344A uses an E1344-80001 terminal assembly.
Component Assembly
Description
The E1343A Component Assembly consists of 16 channel relays and four
tree switch relays. The channel relay switches are separated into two banks,
Bank 0 (channels 00 through 07) and Bank 1 (channels 08 to 15). Each bank
has its own common H, L, and G terminals that connect to the channel
switches.
The Bank 0 channel switches also connect to the AT Tree Switch Terminals
(on the terminal module) via the AT Tree Switch (Channel 90) and three
protection resistors (R26, R27, and R28). The Bank 1 channel switches
connect to the BT Tree Switch terminals (on the terminal module) via the
BT Tree Switch (Channel 91) and three protection resistors (R29, R30, and
R31).
The AT2 Tree Switch (Channel 92) connects Bank 1 channels to the AT
Tree Switch. For the E1347A only, the RT Tree Switch (Channel 93)
connects the thermistor (on the terminal module) to the Bank 1 channel
common. This allows measurement of the thermistor to compensate for
temperature measurements made with thermocouples.
The AT Tree Switch connects to the H, L, and G connections on the Analog
Bus Connector and the BT Tree Switch connects to the I+, I-, and IG
connections on the Analog Bus Connector. The Analog Bus Connector
provides direct channel connections between multiple multiplexer modules
and connections between a multiplexer module and E1326/E1411
multimeters.
Each Bank 0 and Bank 1 Common line and AT and BT Tree Switch line has
a 100Ω resistor in series to provide relay contact protection. The Analog
Bus Connector also has six 100Ω resistor in series to provide current
protection.
Terminal Module
Description
The terminal module provides connections from user devices to the
multiplexer. The terminal module also provides connections for
multimeters, voltmeters, counters, and other measuring devices. For the
E1344A only, a thermistor is mounted on the terminal module.
50 Service Chapter 4