# ECU Monitor

Syrus 4G IoT Telematics Gateway has a built-in ECU interface, which allows the device to connect to a vehicle's CAN bus and read data.

General Overview

  • The way it works is that you instruct the Syrus to read data at a certain speed for a particular protocol, for example read J1939 data at 250KHz from the PRIMARY CAN wires on the device.
  • Once the corresponding wires are connected to the vehicle's CAN bus, the ECU will parse the parameters found in the corresponding parameter file inside the device.
  • By default Syrus 4G comes loaded with a predefined list of common parameters, but this list is editable by the user, so they can expand or select only the parameters he/she wants.
  • Once the parameters are being read you can use an application like SyrusJS to obtain the engine data and send it to an endpoint or create rules/trigger actions based on the values reported.
  • You can also use the Syrus 4G to log data from the CAN bus and interpret any proprietary parameters found, provided that you know how to interpret them, more details here.

# Configuration

The recommended way to configure the ECU is by uploading the configuration (ecumonitor.conf) file using Syrus Cloud, this way you can manage and synchronize the same configuration file across multiple devices. Another way to configure the ECU is to use the Management Tool GUI, this method uses the apx-ecu core tool commands in the background to configure the ECU.

Note that if you configure the ECU using the management tool (or apx-ecu system tool) it overwrites the configuration instructions set in the ecumonitor.conf file.

# Configuration Section

The configuration section of the ecumonitor.conf file starts with START_SECTION: CONFIGURATION and ends with END_SECTION.

# Sample ecumonitor.conf file
START_SECTION: CONFIGURATION
...
END_SECTION

Within the section you can define the configuration interfaces and listen only mode:

Interface/Mode Type Description
PRIMARY_CAN String Primary CAN configuration (CAN1_H / CAN1_L wires)
SECONDARY_CAN String Secondary CAN configuration (CAN2_H / CAN2_L wires)
LISTEN_ONLY_MODE String Program the listen only mode

followed by a : and the value for that interface/mode:

START_SECTION: CONFIGURATION
PRIMARY_CAN: VALUE
SECONDARY_CAN: VALUE
LISTEN_ONLY_MODE: VALUE
END_SECTION

The possible VALUES for the interfaces are:

PRIMARY_CAN or SECONDARY_CAN

  • DISABLED
  • J1939_250KHZ
  • J1939_500KHZ
  • ACCESSORIES_XXXXYHZ

Note: Where XXXX is the baud rate, and Y is either K (Kilo) or M (Mega).

and the listen only mode values are:

LISTEN_ONLY_MODE

  • NONE
  • PRIMARY_CAN
  • SECONDARY_CAN
  • PRIMARY_N_SECONDARY
  • ALL
# Sample configuration section for the ecumonitor.conf file
# Sets the primary CAN to read J1939 at 250KHz
# Disables the secondary CAN interface
START_SECTION: CONFIGURATION
PRIMARY_CAN: J1939_250KHZ
SECONDARY_CAN: DISABLED
LISTEN_ONLY_MODE: NONE
END_SECTION
# Sample configuration section for the ecumonitor.conf file
# Sets the primary CAN to read J1939 at 500KHz
# Sets the secondary CAN to accessory mode at 500KHz (compatible with Movon accessory)
START_SECTION: CONFIGURATION
PRIMARY_CAN: J1939_250KHZ
SECONDARY_CAN: ACCESSORIES_500KHZ
END_SECTION

Listen Only Mode

In this mode the ECU Monitor does not request parameters to the vehicle's onboard computer. This is useful in case there's any interferences caused when connecting a diagnostic tool like the ECU to the vehicle's CAN bus.

Once you've configured the ECU, you're ready to connect it to the vehicle's J1939/CAN bus connector, this is usually a 9-pin connector, refer to our support site (opens new window) for more information on the location of this connector.

# System Tool

The apx-ecu core tool can also be used to configure the ECU, for example:

# sudo apx-ecu configure [INTERFACE] [PROTOCOL|CAN_MODE]

# Configure PRIMARY_CAN (CAN1_H / CAN1_L wires) for J1939 at 500KHz
$ sudo apx-ecu configure PRIMARY_CAN J1939_500KHZ

# Installation

Syrus 4 Datasheet with Pinout (opens new window)

CAN Bus Wiring Pinout (found in 14-pin molex)

Syrus Wire Color Signal Description
Yellow CAN1_H Primary positive signal of the J1939/FMS bus. Connect to the vehicle's CAN_H cable. This cable is twisted together with the green CAN1_L cable.
Green CAN1_L Primary negative signal of the J1939/FMS bus. Connected to the vehicle's CAN_L cable. This cable is twisted together with the yellow CAN1_H cable on the ECU Monitor.
Cyan CAN2_H Secondary positive signal of the J1939/FMS bus. Connect to the vehicle's CAN_H cable. This cable is twisted together with the white/light green CAN2_L cable.
White Light green CAN2_L Secondary negative signal of the J1939/FMS bus. Connect to the vehicle's CAN_L cable. This cable is twisted together with the cyan CAN2_H cable.
Last Updated: 6/28/2021, 11:14:30 PM