ENMET MX-52 - Manual (Page 19)

MX52 C ONTROL ENMET Corporation
15
5.2.4 Fault Thresholds
Processing of detector faults, Each channel detects the following faults.
For toxic and explosive gas detectors:
line interrupted (0 mA),
line short-circuited or excessive consumption,
negative offset (more than 20% of measuring scale),
line in calibration mode (2 mA) (if confirmed by programming).
For sensor/transmitter for combustible gas type (4-20 mA and 340 mA) in normal mode, if the measurement is greater
than 100% of the measuring scale, the following occur immediately:
Display: SUP
The relays are actuated if the thresholds are exceeded.
The general fault relay is actuated.
The 4-20 mA output of the channel is greater than 20 mA.
All these states are memorized and the only way of acknowledging them is to switch off the channel and then
restart it.
Faults are valid after a preprogrammed time (in the same way as alarms).
* The LED is extinguished as soon as the fault disappears.
END
START
Wait until the fault has been present
for at least 5 seconds.
The relays are locked in their current state.
The common fault relay is engaged.
The buzzer is engaged.
The channel fault LED is illuminated. *
1 mA is sent on the 4-20 mA output.
Block Diagram 4: Fault
5.2.5 Standard Display
One minute after starting up, and if no test action is performed on the keypad, the unit successively scans all the
channels in service and displays the values.
OR
Examples of display:
Each channel is interrogated for 10 seconds.
The user can interrogate a channel manually by selecting that channel with the + and – switches to obtain a
manual display for one minute.
The user can return to normal cyclic scanning during that one-minute period by simultaneously pressing the + and
– switches. The display panel then shows alternating displays, three times in succession:
For example:
THEN
Channel 1
XXX LEL CH4
Channel 2
XXX ppm Cl2
Channel 5
XXX ppm CO
normal scan
XXX ppm CO