Electrical Specifications
TM794200
Rev Ad, March 2019
35
4.2.3
Relay Output:
The detector may include up to 3 of the following relays depending on the
wiring configuration selected.
Table 10: Dry Contact Relays
Relay
Type
Normal
Maximum Ratings
Alarm*
SPST
N.O.
2A at 30VDC
Accessory* SPST
N.O.
2A at 30VDC
Fault**
SPST
N.C.
2A at 30VDC
* Alarm and accessory relays are normally de-energized open. When in
the Alarm or Warning status, the appropriate relay is closed.
** Fault relay is normally energized closed and the contact will be closed.
When it is in Fault status, the relay is opened.
4.2.4
HART Protocol
The HART protocol is a digital communications signal at low level on top of
the 0
–
20mA.
This is a bi-directional field communications protocol used to communicate
between intelligent field instruments and the host system.
Through the HART protocol the detector can:
•
Display setup
•
Reconfigure setup
•
Display detector status and definition
•
Perform detector diagnostics
•
Troubleshoot