User`s manual

138 cHAPTER 8: Service
Model 335 Temperature Controller
8.10.1 IEEE-488
Interface Connector
Connect to the IEEE-488 Interface connector on the Model 335 rear with cables spec-
ified in the IEEE-488 standard. The cable has 24 conductors with an outer shield. The
conn
ectors are 24-way Amphenol 57 Series (or equivalent) with piggyback recepta-
cles to allow daisy chaining in multiple device syst
ems. The connectors are secured in
the receptacles by two captive locking screws with metric threads.
The total length of cable allowed in a system is 2 m for each device on the bus, or 20 m
maximum.
The Model 335 can drive a bus of up to 10 devices. A connector extender is
required to use the IEEE-488 interface and relay terminal block at the same time. 
FIGURE 8-7 shows the IEEE-488 interface connector pin location
and signal names as
viewed from the Model 335 rear panel.
IEEE-488 interface
123456789101112
131415161718192021222324
IEEE-488 rear panel connector details
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
FIGURE 8-7
TABLE 8-6