Installation Manual

Electrical & Electronic Application And Installation Manual
Production Release Version 1.0
Page 248 12/16/2014
20.2 J1939 Section 71 – TSC1 Operation
20.2.1 Torque Speed Control (TSC1) Operating Principles
The TSC1 message is a J1939 PGN designed to allow the Torque/Speed
control of an engine via the CAN bus. This message can be used by any
electronic control module to request or limit the engine speed / torque output.
Some of the features primary uses are; direct engine speed control via a
machine controller (removes the need for a fixed throttle connection to the
engine ECM), or the limiting of engine speed / torque during transmission gear
changes.
The OEM is responsible for ensuring that the implementation of TSC1 speed
control is safe and appropriate for the engine and machine. Furthermore it is
necessary for the OEM to perform a risk assessment validation of the
machine software and hardware used to control the engine speed via TSC1.
20.2.1.1 Engine Speed Control
When correctly configured the speed control feature of the TSC1 message will
directly control the engine speed. This means that desired engine speed will
be set to the value contained within the TSC1 message. The engine will then
respond to this request and attempt to reach the desired engine speed value.
It should be noted that the TSC1 speed control message will override all other
engine speed demand inputs such as analogue and PWM throttles. The only
speed input available, which is not overridden by the TSC1 message, is the
intermediate engine speed feature as, described in section 11 of this guide.
20.2.1.2 Engine Torque Control
TSC1 torque control offers the user the same type of function as the speed
control feature but with the input being a torque control value. By controlling
engine torque output the controlling device is actually requesting an engine
delivered fuel quantity from the engine ECM. Care must be taken when
operating this mode as controlling engine fuelling can lead to unpredictable
engine behavior (and speed) especially when implemented under transient
load conditions.
Note: This feature must not be implemented without consulting the
Applications Engineering department and a full FMEA/risk assessment
must be carried out by the customer.
20.2.1.3 Engine Speed Limiting
Engine speed limiting is a feature, which enables a machine controller to
request a physical engine speed limit value as opposed to a speed control.
Under this configuration the additional throttle inputs available on the machine
will remain active, only up until the TSC1 transmitted speed limit is reached.
For example; if the TSC1 message is set to Speed limit with a value of
1800rpm, the operators foot throttle will remain active and the engine will
respond to any speed requests form the pedal. However if an engine speed