Reference Manual
00809-0100-4841, Rev. AA
May 2007
Rosemount 3490 Series
4-42
In a basic filling applications, the On point (e.g. P411) is programmed to be
less than the Off point (e.g. P412). Relay 1 in this case will energise when the
PV value (D800) drops below the On point (P411) and de-energise when the
PV value rises above the Off point (P412).
When the relay mode is "Set Point" (as above), the PV value is used to control
the relays. There are set point modes for the SV value (D801), TV value
(D802) and FV value (D803). For details of these, see Section “Transmitter
inputs to the 3490“ on page 4-13.
Relay Safeguard Options
Menu: MAIN MENU / SETUP / [CONTROL UNIT /] OUTPUT / RELAY
P413 RL1 Min On (Factory default: 0:00 m:s)
Defines the minimum time (minutes and seconds) that relay RL1 will stay
energised before de-energising. This is an optional override (safeguard) to
allow sufficient time for connected equipment to respond.
P414 RL1 Max On Factory default: 0:00 m:s)
Defines the maximum time (minutes and seconds) that relay RL1 will stay
energised before de-energising. This is an optional override (safeguard) to
prevent overuse of connected equipment.
P415 RL1 Min Off (Factory default: 0:00 m:s)
Defines the minimum time (minutes and seconds) that relay RL1 will stay
de-energised before energising. This is an optional override (safeguard) to
avoid overuse of connected equipment.
P423 to P425 are the equivalents for relay RL2
P433 to P435 are the equivalents for relay RL3
P443 to P445 are the equivalents for relay RL4
P453 to P455 are the equivalents for relay RL5
Alternative Duties
Relays can perform alternative duties beside the "On/Off point control"
operation described in Section “On/Off Point Control“ on page 4-42.
Menu: MAIN MENU / SETUP / [CONTROL UNIT /] OUTPUT / RELAY
P410 Relay 1 Mode (Factory default is "None")
P420 Relay 2 Mode (Factory default is "None")
P430 Relay 3 Mode (Factory default is "None")
P440 Relay 4 Mode (Factory default is "None")
P450 Relay 5 Mode (Factory default is "Fault")
Table 4-11 on page 4-44 lists all relay modes (duties) and what they do. Relay
modes automatically enable and disable special control functions, special
alarms and pumped volume totalising as shown in Table 4-12 on page 4-45.
Descriptions of the relay modes and the auxiliary functions follow Table 4-12.
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