31
DRM simply monitors the NGR resistance for continuity, i.e. whether, or not, the NGR is open, or presents some
resistance.
The DSP-DRM has one Form C output relay which can be used to give a door/panel mounted or remote indication of
an NGR fault.
DSP-DRM Operation with DSP-OHMNI system
A DSP-DRM module must be present in the lineup of feeder modules In order to monitor the system ground resistor.
If the NGR is ok then the STATUS page shows NGR MONITORING NGR OK. The ‘LOW V’ indication may or may not
be seen. It depends on the voltage that is measured across the NGR grounding resistor. Normally this voltage will be
low or zero in the absence of a ground fault. If sufficient NGR voltage develops then the DSP-DRM will begin to moni
-
tor the resistance value of the NGR and signal out-of-tolerance if necessary. Measurement of the actual resistance
of the NGR depends on the existence of at least 5% of NGR rated voltage otherwise LOW V is indicated. If this is
displayed then the DSP-DRM will only monitor the NGR for continuity i.e. not open or short circuit.
Figure 31: NGR Measured Ok
Figure 32: NGR Status Good Resistor
Summary of Contents for DSP-OHMNI
Page 1: ...C EG30EM Instruction Manual V2 June 2020 DSP OHMNI ...
Page 11: ...9 Figure 1b DSP DCM Wiring Figure 1c System Module DSP DSM Wiring ...
Page 12: ...10 Figure 1d Power Supply DSP DPS Wiring Figure 2 Preferred Feeder Module DSP DFM Wiring ...
Page 45: ...43 Figure 41 DSP DPS System Module Connection ...
Page 46: ...44 Figure 43 DSP DLM Logging Module Connections Figure 44 DSP TDM Display Module Connections ...
Page 47: ...45 Figure 45 Typical DSP DRM Installation Connections ...
Page 50: ...www i gard com Phone 905 673 1553 Toll Free 1 888 737 4787 Fax 905 673 8472 sales i gard com ...
