Endress+Hauser gammapilot FTG 671, Operating Instructions Manual

Page: 41 / 64

5 Limit Switches - Relays
This Chapter describes the setting of the relay limit switches. It need only be read if the
standard limit detection mode described in Section 4.5, which uses the default settings,
does not satisfy your needs. This might be the case if the detector is mounted vertically
(two widely spaced limits), if the relay acknowledgement mode is required, or if the
switching is to be optimised by changing the integration time.
Gammapilot FTG 671 transmitters have two independent relays, which switch according
to the size of the measured value at V0H0.
•
Each limit switch has a switch-on and switch-off point. The relative values of
these two parameters determines the hysteresis and fail-safe mode, see
Fig. 5.1.
•
Both relays can be operated in acknowledgement mode.
•
The switching precision of the relays can be adjusted by means of the integra-
tion time.
•
The response time is determined by the local dose rate at the detector.
The relays are controlled by the matrix fields V1H0 to V1H4 for relay 1 and V1H6 to V1H9
for relay 2. Table 5.1 lists the configuration parameters. Table 4.2 in Section 4.5
summarizes the response of the relays in minimum and maximum fail-safe mode.
Relay 1 Relay 2 Significance Default
V1H0 V1H5 Relay switch-on point DG 57
DG 17/27
72/38
90/10
V1H1 V1H6 Relay switch-off point DG 57
DG 17/27 38/72
10/90
V1H2 V1H7 Relay operating mode
0 = standard operation
1 = acknowledgement mode
0
V1H3 V1H8 Relay at fault
0 = de-energises
1 = remains in status found at fault (hold)
0
V1H4 V1H9 Relay acknowledgement (V1H2/V1H7 = 1)
Press »E« to acknowledge
V0H4 Integration time - DG 57
Integration factor - DG 17/27 (Z) 7
Table 5.10:
Relay control parameters
Minimum fail-safe mode
switch-off < switch-on point
hysteresis
Relay
energised
Relay
de-energised
Maximum fail-safe mode
switch-off > switch-on point
hysteresis
BA082E30
Switch-on
point Switch-off
point Switch-on
point Switch-off
point
level rises level falls
level falls level rises
d
e
-energi
ses
energ
ises
d
e
-energi
ses
energ
ises
Fig. 5.4:
Selection of minimum and
maximum fail-safe mode by
setting the switch points
Gammapilot FTG 671 Chapter 5: Limit Switches - Relays
39