ETS-Lindgren FM5004 Field Monitor (Archived) - Manual (Page 12)

The FM5004 provides two digital interfaces (IEEE-488 and RS-232), a switch
selectable 0–5 VDC analog output, and audible user selected field strength,
temperature, and low probe battery alarms. It has a probe dependent frequency
response of 10 kHz–40 GHz and a sensitivity of 0.5 V/m–3000 V/m,
15.0 mA/m–30 A/m (probe dependent).
Theory of Operation
For information about a specific probe, see the probe manual.
S YSTEM T HEORY
A complete FM5004 system consists of one to four field measurement probes
coupled to the FM5004 through fiber optic cables, and optional external devices.
The FM5004 contains fiber optic I/O cards to communicate with the probes, a
main processor board, an LCD to display data and system status, a keypad for
operator control, and an audible alarm to indicate field strengths above or below
a user-defined value. RS-232 and IEEE-488 ports are provided for remote
system operation and data collection, and an analog output port is provided for
leveling purposes.
The probes and I/O cards use microprocessors to provide intelligent control and
operation of the system. Each has a self-contained power supply: a universal
input 110–230 VAC supply for the FM5004, and rechargeable battery packs for
the probes.
When a field strength reading is requested by the FM5004, the I/O card for that
probe sends the appropriate command to the probe through the fiber optic cable.
The probe measures the signal level for each enabled axis, a vector addition is
performed on these readings, and then the result is transmitted to the I/O card
through the fiber optic cables. The I/O card formats the data from the probe and
routes it to the main FM5004 processor for interpretation, display, and
transmission to a remote recorder (if desired).
12 | Introduction
Archived 10/19/10