Endress+Hauser prolevel FMC 661 - Page 37

Example:
min. fail-safe mode,
relays 1a, 1b:
switch point 10%,
hysteresis 40%
relay de-energises on
alarm
# Matrix Entry Remarks
1 V1H0 e.g. 10 Switch point
2 - »E« Register entry
3 V1H1 0 Min. fail-safe mode
4 - »E« Register entry
5 V1H2 e.g. 40 Hysteresis —
relay energises at 50
6 - »E« Register entry
7 V1H3 0 De-energise on alarm
8 - »E« Register entry
9 V1H4 1 Assign to channel 1
10 - »E« Register entry
Example:
max. fail-safe mode,
relay 2a, 2b
switch point 90%
hysteresis 40%
relay follows analogue
output
assigned to channel 1
# Matrix Entry Remarks
1 V1H5 e.g. 90 Switch point
2 - »E« Register entry
3 V1H6 1 Max. fail-safe mode
4 - »E« Register entry
5 V1H7 e.g. 40 Hysteresis ——
relay energises at 50
6 - »E« Register entry
7 V1H8 1 Follow outputs
8 - »E« Register entry
9 V1H9 1 Assign to channel 2
10 - »E« Register entry
Note!
• The switch point and hysteresis are always entered in the units of calibration or
linearisation
• A small hysteresis prevents faulty switching due to turbulence
• A large hysteresis allows two-point control of a pump with one relay
• For two pairs of relays on channel 1, the hystereses can set such that one pair of
relays de-energises just as the other energises.
11 12 13
21 22 23
rua
11 12 13
21 22 23
rua
rising
falling
de-energises
hysteresis. e.g. 40% V1H2
relay
energises
switch
point
V1H0
BA142_41
e.g. 50%
e.g. 10%
Fig. 4.15:
Limit value relay: example for minimum fail-safe
mode
31 32 33
41 42 43
rua
31 32 33
41 42 43
rua
rising
falling
relay
de-energises
hysteresis. e.g. 40% V1H7
energises
switch
point
V1H5
BA142_42
e.g. 50%
e.g. 90%
Fig. 4.16:
Limit value relay: example for maximum fail-safe
mode
Note!
Prolevel FMC 661 Chapter 4: Level Measurement
Endress+Hauser 33