Appendix 6: Overview Of The Fs24X Plus™ Modbus Interface - Honeywell FS24X Plus User Manual

CHAPTER
9
The FS24X Plus™ Flame detector communicates status using a variety of channels including the
HALO light ring flash pattern, a 4-20 mA current loop with HART®, three relays, RS-485 and USB.
The current loop is designed for use in systems designed for safety integrity level (SIL) 2 as defined
by EN 61508.
The relay outputs are designed for use in SIL 1 systems. The digital interfaces (RS-485 and USB) do
not have any SIL rating but are still useful because of the data they provide.
The USB interface is not accessible when the enclosure is closed and is used for initial set-up or
post event diagnostics or maintenance.
The RS-485 interface can communicate in two modes: either Honeywell® proprietary FP2 or
standard Modbus. The configuration of the detector can be manipulated over USB or RS-485/FP2
but not standard Modbus. This section describes RS-485/Modbus.
Communications Capabilities.
The RS-485 port can be configured for speeds of 9600, 19200, 38400, 76800, or 115200 baud with
a default of 9600 baud. Each byte can have even, odd, or no parity with a default of even parity.
Additionally, each byte can have one or two stop bits with a default of one stop bit. These parameters
are set on the Configure/Fieldbusses tab of Honeywell® FlameManager . After the settings are
changed, the detector must be rebooted before they take effect. The Modbus interface is
implemented entirely as holding registers as listed in Table1. Writing is not permitted.
First MB Reg Last MB Reg
40003 40004
40005 40005
40007 40007
40008 40008
40015 40015
40016 40016
40017 40017
40037 40038
40039 40039
40040 40040
40042 40042
40043 40043
40044 40044
Honeywell® FS24X Plus™ |
Appendix 6: Overview of the FS24X Plus™ Modbus
Interface
Table 1. Modbus Holding Registers
Datatype
float32
uint16
uint8
int16
int16
int16
int16
float32
int16
int16
int16
int16
int16
User Manual
Description
Alarm Level (0,1, or 2)
The most important active fault
Monitoring State (See Table 2)
Heartbeat counter
Temperature 1 (ºC *10)
Temperature 2 (ºC *10)
Temperature 3 (ºC *10)
Output Current (mA)
External 24 VDC supply (mV)
Internal 3.3 VDC supply 1 (mV)
Internal 3.3 VDC supply 2 (mV)
Internal 30 VDC supply (mV)
Internal 320 VDC supply (Volts)
100