Owner's Manual

GDX-350 Sensor Transmitter
44 P/N: 5600-9001 Rev 2
5.12. HELP Screen
The HELP screen contains several pages of information describing how to operate the GDX-350. This is
the bottom menu on page 1 of the SETUP screen.
5.13. Diagnostics
IMPORTANT: Gas monitoring and alarm processing are not performed while using the
Diagnostics menus. Access requires a special key sequence of four consecutive UP
keystrokes.
There are two Diagnostics menus useful for driving outputs without exposing the sensor to the target
gas. The OUTPUT SIMULATION menu allows for setting of the 4-20 mA output to virtually any desired
value. This is useful for checking responses of devices receiving the GDX-350’s 4-20 mA output. The
ACTIVATE RELAYS menu allows for tripping of the alarm relays (if equipped) without tripping alarm set-
points with the target gas.
* * * WA R N I N G * * *
A l a r m p r o c e s s i n g w i l l
b e h a l t e d d u r i n g
d i a g n o s t i c mo d e !
E D I T t o c o n t i n u e .
A n y o t h e r k e y t o e x i t .
D I A GN OS T I C S
Ou t p u t S t i mu l a t i o n
R e l a y T e s t
OU T P U T S T I MU L A T O R
Ou t p u t 4 . 0 mA
E D I T t o c h a n g e .
N e x t t o e x i t .
EDIT
A C T I V A T E R E L A Y S
R e l a y 1 O F F
R e l a y 2 O F F
R e l a y 3 O F F
Figure 5-17: Diagnostics Menus
5.14. RS-485/Modbus Setup
The RS-485 MODBUS SETUP menu allows setting the RTU address (if RS-485 equipped) for each
GDX-350 on the RS-485 network. Each GDX-350 must have a different RTU address when
communicating on the same 2-wire cable. Baud rate, parity and stop bits are fixed at industry standard
values of:
• Baud Rate: 9600
• Parity: None
• Stop Bits: 1.
R S 4 8 5 MOD B U S S E T U P
R T U A d d r e s s 1
B a u d R a t e 9 6 0 0
P a r i t y N o n e
S t o p B i t 1
Figure 5-18: Modbus RS-485 Setup Menu