Service manual

Terminal module connections include H, L, and G terminals for Channels

00 - 15, Bank 0 and Bank 1 Commons, and the AT and BT Tree Switches.

In addition, each channel H line has a jumper on the terminal module that

can be removed to add filter components, attenuators, or current shunts.

E1345A/47A

Multiplexer

Descriptions

The E1345A 16-Channel Relay Multiplexer and the E1347A 16-Channel

Thermocouple Relay Multiplexer modules consist of an E1345A

component assembly ( E1345-66201) 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 E1345A and E1347A.

The only difference between the two component assemblies is their jumper

settings. The E1345A has an E1345-80001 terminal module and the

E1347A has an E1347-80001 terminal module.

Component Assembly

Description

The E1345A 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.

Chapter 4 Service 51