PDM systems are digital structures for analog (current, voltage, etc.) and binary (contacts, etc.) quantity acquisition, allow the temporary storage of the acquired information and its transfer to a computer for storage and processing (post-fault analysis, monitoring, etc.). Some versions allow local data storage and subsequent retrieval for post-fault analysis. PDM-type units are managed through a dedicated Windows compatibile software package, which can run on most computing systems currently in use.

Main technical features of PDM 03XAF type digital modular perturbograph:

analog input quantities: 9 channels (configurable currents and voltages, Input current = 1 or 5 A AC, Input voltage = 60 or 100 V AC); 12-bit resolution;
binary input quantities: 32 channels;
input sampling frequency: 1000 Hz;
supply voltage: 220 V DC or AC;
recording triggering: transition of binary inputs (programmable), exceeding of analog input thresholds (programmable), by another PDM-type device, manually;
recording time: approximately 193 sec recording time, with programmable pre-alarm, alarm, and post-alarm time;
real-time clock;;
proper operation self-testing and fault status signaling;
serial communication line for long-distance data transmission, current loop or RS485 (1 km maximum);
RS232 serial line for local communication, by connecting a portable computing device;
event synchronization line for multiple PDM-type units;
ON-LINE operation and the ability to configure multiple PDM-type units into a distributed monitoring and recording system;
synchronization line for analog signal acquisition;
communication, analysis, and management software;
overall dimensions 220 mm / 115 mm / 170 mm;
approx. weight of 3 kg;
easy mechanical and electrical installation at the location where the electrical quantities will be acquired.