9.10.3 Limit Value Responses
Relay Allocation
As standard, both limit values of all measuring points of a device or of a
measuring circuit board are used for fault alarms (see 9.5), i.e. if an exceeding
of a limit value occurs at any measuring point, the relay 0 responds if an alarm
relay cable or the corresponding relay adapter (see manual 5.2/3) is used. It
only opens again, after all measured values have dropped below the limit
values by as much as the hysteresis. If a limit value has not been defined, the
measuring range limit will be used as limit value. A sensor breakage will always
cause a fault alarm.
To distinguish between max value exceeding and min value undershooting the
alarm signal generators can be re-programmed to variant 1 (see manual
6.10.9).
However, if it is necessary to selectively identify and evaluate faults, the
function ´Response Max´ or ´Response Min´ can be used to allocate individual
relays to the limit values. It is also possible to allocate several limit values to
one relay. For this purpose the relay cables provide 2 relays (0 and 1) and the
relay adapter (ZA 8000-RTA) provides 4 relays (0 to 3). This mode also has to
be set as variant 2 in the output module (see manual 6.10.9).
Socket A2:
Setting the relay module to variant 2:
EA Trigger-Alarm
(relay int. allocated)
2: Rx int. allocated
Activating relay x at limit value exceeding Max:
Action Max: -----
Rx
Activating relay y at limit value undershooting Min:
Action Min: -----
Ry
Clearing the relay allocation using the key:
<CLR>
Starting and Stopping a Measurement
Exceeding of limit values can not only be used for fault alarms but also to start
or stop a measurement (see manual 6.6.3). The start command or stop com-
mand is assigned to a limit value - by means of the ´Special functions´ menu
and function ´
Action Max
´ or ´
Action Min
´.
Starting the meas. at exceeding of limit value Max:
Action Max:
--
Start
Stopping the meas. at undershooting of lim.value Min:
Action Min:
--
End
Clear response by using the key:
<CLR>
Beim Ausdruck der Fühlerprogrammierung (s. Hb. 6.10.1) erscheint bei Aktion
Max (AH) und Min (AL) ein zusammengesetzter Code für Start/Ende
S
/
E
(s.
Hb. 6.6.3) und Relaiszuordnung
x
(s. Hb. 6.10.8).
ALMEMO
®
2590-9
57
Special Functions
