Middleby Marshall PS200, PS570 manual Section Servicing Components, Original-style speed controller

SECTION 3 - SERVICING COMPONENTS

SECTION 3

SERVICING COMPONENTS

I.CONVEYOR SPEED CONTROLLER AND DRIVE MOTOR

The Conveyor Speed Controller is used to set and monitor the speed of the conveyor. The Controller consists of three components:

•Control Module

Early units used a module which featured a microcom- puter that was unique to each oven model. Using this control module required verifying that the correct mi- crocomputer was installed.

Later units use DIP switches to set up the controller for a particular oven model. This later model was initially available with a thumbwheel unit (either 4 or 8 DIP switches). Current models feature a digital display with keypad (8 DIP switches).

•Thumbwheel Unit (or Digital Display with Keypad)

This module displays the conveyor speed and allows it to be adjusted by the operator. It is connected to the control module by a ribbon cable.

•Pickup Assembly

The pickup assembly consists of a magnetic wheel on the end of the gear motor (conveyor drive motor) shaft, and a Hall Device sensor that provides feedback to the control module.

As the magnetic wheel turns, the revolutions of the magnet are monitored by the Hall Device sensor. The signals are sent to the control module, which compares the motor speed with the speed shown on the thumbwheel or digital display. The control module in- creases or decreases the voltage to the gear motor (conveyor drive motor) depending on the signal.

Figure 12

Original-style speed controller

Produced with thumbwheel only.

Interchangeable microcomputer selects oven model.

THIS CONTROLLER IS OBSOLETE AND NO

LONGER AVAILABLE.

Control module Microcomputer

A. Part Number Reference - Speed Controllers

1.Original-style speed controller with interchangeable mi- crocomputer and thumbwheel. This unit is no longer available and part numbers are provided for reference only. Servicing this unit is beyond the scope of this manual. If this controller is in need of service, we rec- ommend simply installing a current unit (see below).

P/N Description

28174-0004 PS360 controller, yellow (12A) microcomputer

28074-0006 PS360 microcomputer, yellow (12A)

27170-0232 PS360 microcomputer w/emulator, yellow (12A)

28074-0007 PS314 controller, orange (13A) microcomputer

28074-0008 PS314 microcomputer, orange (13A)

27170-0233 PS314 microcomputer w/emulator, orange (13A)

28074-0013 PS200 microcomputer, pink (15A)

2.Current-style speed controller with either 4 or 8 DIP switch settings and thumbwheel. This unit is no longer available from the factory, but may still be stocked by service agen- cies.

P/N Description

42810-0133 Controller assembly with thumbwheel

42810-0118 Thumbwheel only

3.Current-style speed controller with 8 DIP switch set- tings and digital display/keypad. Note that the two types of controllers ARE NOT compatible - the controller and display unit MUST be of the same type.

P/N Description

37337 Controller assembly with digital display/keypad, NCC (8/00-current)

37503 Digital display/keypad unit only, NCC

45133 Controller assembly with digital display/keypad, Danaher (2/02-current)

Figure 13

Current-style speed controller

Produced with Thumbwheel or digital display.

4 or 8 DIP switches select oven model.

DIP switches may	Cover plate
be on control	shows DIP
module or digital	switch settings
display, depending
on the controller	Thumbwheel
model.
	or digital
	display

Control module

Thumbwheel

13