ProtEX-MAX PD8-7000 Explosion-Proof Temperature Meter Instruction Manual
37
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 modules, or using the F4 digital input, which is triggered with a contact
closure to COM, or with an active low signal (see page 20).
When the ACK button or the assigned digital input is closed, all relays programmed for manual reset are
acknowledged.
Figure 20. Acknowledge Relays w/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
Relays 1 & 2 are energized when SW1 & SW2 switches are closed and the front panel LEDs are off. If
the contact to the digital input is opened, the corresponding front panel LED flashes indicating this
condition. The processes being controlled by the interlock relay stop and will re-start only after the
interlock relay is activated by the digital inputs.
+5
I1
I2
I3
I4
O1
O2
O3
O4
G
DO 1-4
GND
ACK
PDA1044 Digital I/O Module
1
2
3
4
5
6
7
8
9
10
DI 1-4
1
2
3
4
5
6
+5
I1
I2
I3
I4
O1
7
8
O2
O3
9
10
O4
G
DI 1-4
DO 1-4
5 VDC
GND
SW2
SW1
