5.2 External limit switch
Level measurement with
level switching
Operating mode 0 (V8H0 = 0) of the Prolevel FMC 661 allows level measurement on
channel 1 and separate level switching on channel 2:
# Matrix Remarks
1 V9H5/V3H5/V3H6 Reset, enter sensor constants
2 V8H0 Select and register operating mode 0 (=0)
3V0H1
…
V0H7 Level calibration, analogue output, Chapter 4.
4V8H2
…
V8H6 Calibrate limit switch, capacitance p. 37, Liquiphant p 38.
5V1H0
…
V1H4, V1H6 Set relays, for limit switch set fail-safe mode only
Level limit switchingOperating mode 2 (V8H0 = 2) provides level limit switching on channel 2 only. The limit
switch calibration is as described under "Sensor calibration", capacitance probes p. 37,
Liquiphant, p 38. For a top-mounted capacitance switch there is an additional delay, see
Table 5.1:
•
Set the relay fail-safe mode only
•
If V1H4 = 2 (channel 2), copy the values in V1H5/V1H7 to V1H0/V1H2.
Endress+Hauser
PROLEVEL
FMC661
123.4
1A
1B
2A
2B
3
HV
+
E
_
capacitance probe
channel 1
hydrostatic
sensor
BA142_47
Liquiphant
channel 2
max. fail-safe mode
Fig. 5.5:
Level measurement and limit
switching on separate channels
Product Dielectric
constant εr
Conductivity Switch point
with ground tube without ground
tube
Solvents, oil, fuel <3 low ca. 150 mm ca. 500 mm
dry bulk solids <3 low ca. 350 mm
(cable probe)
moist bulk solids >3 medium ca. 150 mm
(cable probe)
Table 5.1:
Switch point deviation as a
function of product for top
mounted capacitance probes and
default value of 1 Hz = 5 pF
Prolevel FMC 661 Chapter 5: Level Measurement with Limit Switch
Endress+Hauser 39
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