maxPAC Hardware Reference Guide
Metso Automation MAX Controls Inc. • 277596 •
3-2
DPU. This LED blinks on and off at a constant rate when the module is not
being scanned by the DPU.
Bus Address
This module supports two modes of operation selected by jumper setting.
For use with DPU4A/B this module requires 16 addresses and provides 15
channels.
When used with DPU4E, the module only requires two addresses and
provides 16 channels.
Jumper Configuration
The module contains two jumpers. Refer to the following table for jumper
setting information.
Jumper Installed Not Installed
W1 50 Hz 60Hz
W6 DPU4A/B DPU4E
Module Operation
This microprocessor-based module supports up to 16 4-20 mA inputs, all
powered from a local 24V loop supply. A sigma delta A/D and reference are
provided for each input. Each A/D constantly reads the voltage generated by
the input and converts the differential measurement to a 15-bit plus sign
binary value, which is read by the microcontroller.
The digital filter in the oversampling A/D provides excellent 50/60 Hz
normal mode rejection. Immediately following each measurement, open
input and over range conditions are checked. A DC/DC converter provides
isolated power to the A/D measuring circuit. Communication between the
microcontroller and the A/D is serial at 100kHz. Optical isolators provide
the isolation between the A/D and the serial logic circuits.
The microprocessor provides the input data to the DPU on demand via the
bus FPGA. The FPGA provides the I/O bus interface logic; its program is
loaded from the FLASH on power up. Module calibration is done
automatically at power up following startup diagnostics. Calibration is
repeated periodically online to compensate for temperature effects.
To Next Page
Loading...
Need help?
General