maxPAC Hardware Reference Guide
Metso Automation MAX Controls Inc.
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277596
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5-2
Bus Address
This module supports two modes of operation selected by the jumper setting.
For use with DPU4A/B this module requires 16 addresses and provides 15
channels. W7 installed
When used with DPU4E, the module only requires two addresses and
provides 16 channels. W7 not installed
Jumper Configuration
The module contains three jumpers. These jumpers are located at the rear of
the module above the edge connector. Refer to the following table for
jumper setting information.
Jumper
Installed
Not Installed
W3
50 Hz
60Hz
W2
Common I/O
Redundant I/O
W6
DPU4A/B
DPU4E
Cold Junction Compensation
If this module is configured by the DPU to perform cold junction
compensation, a thermistor (MAX Part No. 074566) must be installed in
connectors P4 and P5 at the front of the module, above and below the input
connectors.
Module Operation
This microprocessor-based module supports up to 16 TC or emf inputs,
which may be independently configured. A sigma delta A/D reads the
voltage generated by one of the 16 TC or emf inputs and converts the
differential measurement into a 15 bit plus sign binary value representing the
millivolt input which is read by the microcontroller. The microcontroller
initiates the conversion and waits for the conversion to complete.
The digital filter in the oversampling A/D provides excellent 50/60 Hz
normal mode rejection. The A/D also provides a variable gain amplifier
function. Prior to starting each conversion, the microcontroller sets the gain
required in the A/D for each configured input measurement, and selects the
input channel by means of two solid state, optically coupled relays.
The inputs are multiplexed with optical relays to provide channel to channel
isolation. Immediately following each measurement, open TC and over range
conditions are checked. A DC/DC converter circuit provides isolated power