Madman EMS-3 Operating Manual
Page 34
User defined senders:
The EMS-3 has a user sender calibration feature that can be customized for Resistive, 4-
20mA as well as Voltage output pressure senders.
10.12 Senders that are grounded in the engine block
Single wire senders require that their mounting arrangement (thread) has a very good electrical contact with the engine
block. Avoid the use of any sealant or tapes as these may cause a bad electrical connection. Further to this it is very
important that the engine block has a good electrical connection to the negative supply terminal of the EMS-3. Any
voltage drop caused by other equipment on the ground wire will cause incorrect readings. The best way to ensure a good
connection is to wire a single connection between the EMS-3 ground terminal (any of these terminals) and the engine
block. Do not wire this anywhere else and do not allow any other equipment to use this wire as a current return path.
10.13 Analog Channels Dipswitch settings
The EMS-3 unit has the added ability, over its predecessors, to use both resistance and voltage based sensors. In order
to make use of this wider range of sensors, a small bank of on-off switches has been mounted on the input PC board
inside the EMS-3 housing to enable sensor compatibility selection. Use a small screwdriver to change the switch
direction. By default, CH1 + CH2 are ON and CH3 + CH4 are off. Failure to set the DIP switch will not cause damage but
will cause false readings.
In most cases resistive sensors require a biasing voltage to work properly. The switch associated with the required
channel must be in the ON position to enable the sensor to work correctly.
Example: In the image, switch 3 has been switched OFF to enable the
use of a voltage based sensor on the Analogue 3 channel.
Dipswitch
Function
1
Analog Input Channel 1 Pull up resistor
(On=Enable, OFF=Disable)
2
Analog Input Channel 2 Pull up resistor
(On=Enable, OFF=Disable)
3
Analog Input Channel 3 Pull up resistor
(On=Enable, OFF=Disable)
4
Analog Input Channel 4 Pull up resistor
(On=Enable, OFF=Disable)
