The Digital Differential Detector (RDD-TM34) is an electronic device whose purpose is to safely certify the efficiency of high static switching signals by constantly monitoring the rms value of the current absorbed by the luminous element of the signal (lamp or LED).
When the current is within the admissible range, the residual current detector keeps a relay (relay Ks) activated.
The current monitoring functionality is carried out according to safety recommendations, by total separation of input and output signals, use of redundant and independent control units, rejection of any non-dynamic input and output signals, activation of the Ks relay by both control units by independent dynamic signals.
The differential detector allows the configuration of the current limits for the Ks relay excitation for both fixed and intermittent high signal systems. It is also possible to set the delay time for de-energizing the KS relay. These settings are made through the corresponding dip-switches, which are protected from tampering by a sealable, transparent door that allows visual inspection.
The device is compatible with FS58 backplanes.
The device is manufactured to SIL4 safety level according to CENELEC EN 50128 and EN 50129. The RD is approved according to RFI specification DTCDNSSSTB SF IS 05 760 B.