METSOmaxPAC Hardware Reference Guide

maxPAC 

Input/Output Subsystem 

Overview 

The maxPAC Input/Output System links the maxDNA Distributed Control 

System to real world process control inputs and outputs. The Input/Output 

system uses a compact design to provide the system with greatly enhanced 

I/O capacity in relatively little space. A close relationship exists, in turn, 

between this I/O system and the maxDNA Distributed Processing Unit 

(DPU) which it serves. 

The DPU and the I/O modules mount in an I/O chassis assembly. The 

backplane in the chassis assembly provides the I/O bus connection between 

the DPU and the I/O modules. It also provides the system power and field 

power connections to the modules. Multiple I/O chassis that share the I/O bus 

can be installed in a cabinet. 

Model IOP I/O Subsystem 

Cabinet 

Two standard cabinet types are available for the mounting of I/O system 

hardware. The cabinet is available as either a NEMA (National Electrical 

Manufacturers Association) type 1 or 12 and consists of the following: 

ƒ Welded steel construction 

ƒ Front and Rear access 

ƒ I/O mounted in front and rear of cabinet (standard) 

ƒ I/O mounted in front and terminations in rear of cabinet (option) 

ƒ Other mounting arrangement options are also available 

ƒ Removable doors 

ƒ 19” rack mount rails with standard E.I.A. hole spacing 

ƒ Top or bottom Cable access 

ƒ Size 85 7/8” h x 24 ¾”w x 38 7/8”d 

Optional Cabinet styles and sizes are also available. 

The following figure shows a typical cabinet arrangement with I/O in both 

the front and rear of the cabinet. 

Figure 1-1. Typical Cabinet Arrangement, Front and Rear Views 

Chassis Assembly 

Three chassis assembly types are available for the installation of the I/O 

module as follows: 

‰ IOP382 Eight-pack assembly to accommodate up to eight maxPAC I/O 

modules. The DPU4F can also reside in this chassis. 

‰ IOP383 Six-pack assembly to accommodate a DPU4E or a Model 564 I/O 

module in the right most position along with six maxPAC I/O modules; the 

DPU4E takes up the equivalent of two maxPAC I/O module positions. 

‰ IOP381 Four-pack assembly to accommodate four maxPAC or Model 564 

I/O modules. 

The rack assemblies contain an I/O backplane featuring edge connectors for 

I/O modules and connectors for 24V system supply and 24V and 48V loop 

power supplies. Input/Output modules connect to the I/O bus through four to 

eight connectors on the backplane, depending on chassis style. 

The backplane also contains ribbon cable connectors to interconnect chassis 

assemblies and extend the I/O bus to the maximum number of modules 

supported by the DPU. 

DPU Mounting 

DPU4E mounts in the right most position of the six-pack chassis assembly. It 

occupies the equivalent of two I/O modules. Refer to Publication 278590 for 

DPU4E information. DPU4F mounts in the left most position of the eightpack chassis assembly. It occupies the equivalent of one I/O module. Refer to 

Publication 278705 for DPU4F information. 

I/O Modules 

The I/O modules are rugged enclosed printed circuit board assemblies. The 

edge connection at the rear of each module provides the interface to the 

backplane and the I/O bus. System power and field power, when applicable, is 

also available through this connection. 

While I/O modules vary by type, they may include one or more of the 

following: 

‰ A color bar on the module faceplate identifies the module type. Each 

module type has a unique color. 

‰ Euro-style terminal connector blocks for field wiring; each block contains 

16 connectors; 

‰ Rotary address switch; 

‰ Light Emitting Diodes (LED) for module status indication; 

‰ All the modules that require field power include a front mounted fuse 

disconnect and a LED fuse status indication; 

‰ All discrete modules include front mounted LEDs for input/output logic 

state; 

‰ The TC module includes front-end connectors with thermistors to measure 

the junction temperature for cold junction compensation. 

The I/O modules may be inserted and withdrawn safely with 24 Vdc and field 

power applied. 

I/O Module Types 

Because of the variety of input and output ranges needed in distributed control 

applications, the Model IOP I/O offers many types of easily configurable 

discrete and analog I/O modules. For a list of modules, along with their 

ranges and number of points per module, refer to the following tables. 

Digital Input (AC/DC)* 

Part Number Description 

IOP330 24 Vdc common input; 16 channels 

IOP334 24 Vdc isolated input; 16 channels 

IOP331 48 Vdc common input; 16 channels 

IOP332 120 Vac/dc isolated input; 16 channels 

IOP333 240 Vac/Vdc isolated input; 16 channels 

IOP350 Form C relay; 10 channels 

IOP351 Form A/B relay; 16 channels 

IOP335 Pulse I/O , 8 channels 

*ac Voltages/currents are RMS