7.4. Rear Panel Connectors

The connectors on the rear panel of the Model 346 are defined below.

Diode / Resistor Sensor Inputs (includes 3401 option card)

Sensor Inputs A through D are DE-9 style connectors. There are two sensor inputs per connector. The diagram on the left (labeled SENSOR INPUTS) shows the general sensor pin grouping per DE-9 connector. Pins 8,9,4,5 belong to one input, and pins 6,7,1,2 belong to the other input. You can use either the C1 to C4 or D1 to D4 pin outs to determine 3401 sensor wiring.

../_images/thermometry_inputs.png

Figure 7.2 Diode / Resistor Sensor Inputs

Pin

Inputs

Symbol

Description

8

A, C1, C3, D1, D3

I+

+ current out

9

I-

- current out

4

V+

+ voltage in

5

V-

- voltage in

6

B, C2, C4, D2, D4

I+

+ current out

7

I-

- current out

1

V+

+ voltage in

2

V-

- voltage in

3

n/a

shield

Sensor measurement common (isolated from chassis)

Heater Output

A 15-pin DA-15 style connector is used for the heater outputs. Each heater return is at the same potential as chassis/earth ground. The compliance voltage of each heater output is 50 V minimum, but can reach as high as approximately 53 V, if the heater resistance is higher than the nominal setting. The maximum current that can be sourced from each heater output is approximately 2 A.

../_images/heater_out.png

Figure 7.3 Heater Output

Pin

Description

8

Heater 1 HI

7

Heater 1 LO

6

Heater 2 HI

5

Heater 2 LO

4

Heater 3 HI

3

Heater 3 LO

2

Heater 4 HI

1

Heater 4 LO

10, 12, 14

Additional chassis/earth ground connections

9, 11, 13, 15

No connect

Digital In / relays / Analog out

A 2 level, 20 pin, 2.5mm terminal block allows access to the following:

Name

Description

Analog Out / 1W heaters

Identifiable as ‘outputs 5-8’, these outputs are 0 to +10V voltage sources, capable of sourcing up to 100mA, at 10V, into a 100Ohm load.

Relays

Two relays, each with a normally open, normally closed, and common terminal. Contact rating of 30VDC at 2A.

Digital Input

Optically isolated inputs that have a safe input voltage range of -5V to +35V, with a max low level input voltage of 1V and a minimum high level input voltage of 4V

5V supply

Isolated +5V supply (100mA max). As an example, it can be used with a relay to drive high impedance digital inputs used for process control in a system.
../_images/aout_din_relays.png

Figure 7.4 Digital In / relays / Analog out

Pin

Description

1

Analog Out 1 +

2

Analog Out 1 -

3

Analog Out 2 +

4

Analog Out 2 -

5

Analog Out 3 +

6

Analog Out 3 -

7

Analog Out 4 +

8

Analog Out 4 +

9

+5V isolated supply

10

+5V isolated supply return

11

Relay 1 normally closed

12

Relay 1 common

13

Relay 1 normally open

14

Relay 2 normally closed

15

Relay 2 common

16

Relay 2 normally open

17

Digital Input 1 +

18

Digital Input 1 -

19

Digital Input 2 +

20

Digital Input 2 -

24VDC Auxiliary Power

A 0.2 in (5.08 mm) 2-pin terminal block allows user-provided 24 VDC to be supplied to the Model 346 to provide auxiliary power to possible future option cards that may require it. The return of this external 24 VDC is connected to the Model 346 chassis ground.

../_images/aux_in.png

Figure 7.5 AUX 24 VDC Input

USB B Connector

../_images/usb.png

Figure 7.6 USB pin and connector

Pin

Name

Description

1

VCC

+5 VDC

2

D-

Data –

3

D+

Data +

4

GND

Ground

Ethernet Connector

../_images/ethernet_connector.png

Figure 7.7 Ethernet pin and connector

Pin

Symbol

Description

1

TXD+

Transmit data+

2

TXD-

Transmit data-

3

RXD+

Receive data+

4

EPWR+

Power from switch+ (not used)

5

EPWR+

Power from switch+ (not used)

6

RXD-

Receive data-

7

EPWR-

Power from switch- (not used)

8

EPWR-

Power from switch- (not used)

IEEE-4888 Interface Connector (optional)

Use the cables specified in the IEEE-488 standard. The cable has 24 conductors with an outer shield. The connectors are 24-way Amphenol 57 Series (or equivalent) with piggyback receptacles to allow daisy chaining in multiple device systems.

The total length of cable allowed in a system is 2 m for each device on the bus, or 20 m maximum. The Model 346 can drive a bus of up to 10 devices. The figure below shows the IEEE-488 interface connector pin location and signal names as viewed from the Model 346 rear panel.

../_images/gpib.png

Figure 7.8 IEEE-488 interface

Pin

Symbol

Description

1

DIO 1

Data input/output line 1

2

DIO 2

Data input/output line 2

3

DIO 3

Data input/output line 3

4

DIO 4

Data input/output line 4

5

EOI

End or identify

6

DAV

Data valid

7

NRFD

Not ready for data

8

NDAC

No data accepted

9

IFC

Interface clear

10

SRQ

Service request

11

ATN

Attention

12

SHIELD

Cable shield

13

DIO 5

Data input/output line 5

14

DIO 6

Data input/output line 6

15

DIO 7

Data input/output line 7

16

DIO 8

Data input/output line 8

17

REN

Remote enable

18

GND 6

Ground wire—twisted pair with DAV

19

GND 7

Ground wire—twisted pair with NRFD

20

GND 8

Ground wire—twisted pair with NDAC

21

GND 9

Ground wire—twisted pair with IFC

22

GND 10

Ground wire—twisted pair with SRQ

23

GND 11

Ground wire—twisted pair with ATN

24

GND

Logic ground