Helios Large Display Temperature Meter Instruction Manual
PD2-7000
36
Acknowledging Relays
There are two ways to acknowledge relays programmed for manual reset:
1. Via the programmable front panel function keys F1-F3 (Default: F3 assigned to ACK).
2. Remotely via a normally open pushbutton wired across one of the digital inputs and the +5 V
terminals on the digital I/O terminal, or using the F4 digital input, which is triggered with a contact
closure to COM, or with an active low signal (see page 18).
When the ACK button or the assigned digital input is closed, all relays programmed for manual reset are
acknowledged.
Figure 24. Acknowledge Relays with Function Key or Digital Input
Setting up the Interlock Relay (Force On) Feature
Relays 1-4 can be set up as interlock relays. To set up the relays for the interlock feature:
1. Access the
Setup
–
Relay
–
Action
menu and set the action to off.
2. In the Advanced features –
User
menu program any of the digital inputs to
Force On
any of the
internal relays (1-4).
3. Connect a switch or dry contact between the +5V terminal and
the corresponding digital input (dI-1 to dI-4) terminal.
Interlock Relay Operation Example
Relays 1 & 2 are configured to energize (their front panel LEDs are
off) when SW1 & SW2 switches (above) are closed. If the contacts to
these digital inputs are opened, the corresponding front panel LEDs
flash indicating this condition. The processes being controlled by the
interlock relay will stop, and will re-start only after the interlock relay is
re-activated by the digital inputs (switches).
Note: If multiple digital inputs are assigned to the same relay, then the corresponding logic is (AND) – i.e.
both switches must be closed to trip the relay.
MENU
RESET
F1
MAX
F2
ENTER
F3
SW1
SW2
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