Metal Samples MS2500L, Operator'S Manual

Page: 6 / 48

2
The MS2500L transmitter is housed in an explosion-proof enclosure with the following ratings:
Housing Ratings:
Class I Groups B,C,D
Class II Groups E,F,G
Class III NEMA 4X
FM Approved CSA Approved
The MS2500L is equipped with 10 feet of transmitter-to-probe cable and uses the standard five-pin
environmental connector found on all of our existing LPR equipment. This light-armor cable passes into
the housing through an explosion-proof cable gland.
Located inside the housing is an electronics package consisting of two printed circuit cards, the mount-
ing bracket for the circuit cards, and all the necessary termination points for the cable and current loop
connections.
The termination points on the printed circuit cards are constructed using removable terminal blocks. This
provides a permanent screw type connection which can break-away from the printed circuit cards for
their easy removal.
The printed circuit cards rest in slide rails within the mounting bracket. Once the terminal blocks are
detached from the printed circuit cards, the circuit cards slide out of the instrument for easy repair,
calibration, or replacement.
B. Principle of Operation
The MS2500L transmitter reads and stores the potential difference between a reference electrode and a
test electrode. It then applies a current through an auxiliary electrode and the test electrode until the
potential measurement between the test and the reference electrodes changes by 10 millivolts. The
instrument then allows this current to settle for a predetermined length of time (polarization cycle), after
which, it samples this current and updates the current loop output using the conversion factor of 5.5 µA
per MPY.
Note: The surface area of the electrode has been adjusted where 5.5 µA converts to 1 MPY.
The polarizing current is then turned off and the cell is allowed to relax for the same length of time as the
polarization cycle.