2Signet 9900 Modbus Module
Caution / Warning / Danger
Indicates a potential hazard. Failure to follow all warnings
may lead to equipment damage, injury, or death
Electrostatic Discharge (ESD) / Electrocution Danger
Alerts user to risk of potential damage to product by ESD,
and/or risk of potential of injury or death via electrocution.
Personal Protective Equipment (PPE)
Always utilize the most appropriate PPE during
installation and service of Signet products.
Refer to your local Georg Fischer Sales offi ce for the most
current warranty statement.
All warranty and non-warranty repairs being returned must
include a fully completed Service Form and goods must be
returned to your local GF Sales offi ce or distributor.
Product returned without a Service Form may not be
warranty replaced or repaired.
Signet products with limited shelf-life (e.g. pH, ORP, chlorine
electrodes, calibration solutions; e.g. pH buff ers, turbidity
standards or other solutions) are warranted out of box but not
warranted against any damage, due to process or application
failures (e.g. high temperature,
chemical poisoning, dry-out) or
mishandling (e.g. broken glass,
damaged membrane, freezing
and/or extreme temperatures).
Thank you for purchasing the Signet line of Georg Fischer
measurement products.
If you would like to register your product(s), you can now
register online in one of the following ways:
• Visit our website www.gfsignet.com.
Under Service and Support click on
Product Registration Form
• If this is a pdf manual (digital copy), click here
Warranty Information
Product Registration
Safety Information
CAUTION
Exercise care when installing module.
Do not bend connecting pins.
Align pins and connectors then push module firmly
into place.
Avoid Electrostatic Discharge (ESD)
● Minimize handling of module to reduce the possibility of
damage due to ESD.
● Handle module by the edges.
● Never touch any exposed circuitry or contacts.
● Wear an anti-static wristband, stand on an anti-static mat, or
keep one hand touching a properly grounded pipe or other
properly grounded piece of metal when handling module.
Power and Output Wiring
Three versions of the Modbus module are available to
accommodate installation site requirements.
Brown
Yellow
Black
White
Gray
D0 (RS485 -) Pin 2
D1 (RS485 +) Pin 1
V+ (12 to 24 VDC) Pin 3
V- (12 to 24 VDC Common) Pin 4
Com/Reset GND Pin 5
Brown D0 (RS485 -)
Yellow D1 (RS485 +)
Black V+ (12 to 24 VDC)
White V- (12 to 24 VDC Common)
Gray Com/Reset GND
Modbus Module
M12 Connector
Male front view
3-9900.270-M3 version: with M12 Connector (Field Mount Only)
Cable assembly with 6” wires with M12 Connector
3-9900.270-M2 version: Terminal board (Panel Mount Only)
Cable assembly with 3” wires, inner-connect to board
3-9900.270-M4 version: Wire Cable
Cable assembly with 6” Wires - pig tail
Brown
Yellow
Black
White
Gray
D0 (RS485 -)
D1 (RS485 +)
V+ (12 to 24 VDC)
V- (12 to 24 VDC Common)
Com/Reset GND
Pin 5
Pin 3
Pin 4 Pin 1
Pin 2
PWR +
PWR -
Loop +
Loop -
Gnd
D0 (RS485 -)
D1 (RS485 +)
Modbus Module
Modbus Module
Reset Switch
Reset Switch
Reset Switch
Loop Voltage
Modbus Module
DC Power
Plug in Module,
directing wires
around Power/OC
terminals. Do not
pinch wires!
3-9900
Panel Mount
Transmitter
Example showing M2 version
For M2 panel installation.
Restrain terminal block assembly
prior to shipping.
