TUBE ASSEM. (L.H.) 8G1221 - Caterpillar

Indication
Messaging
Each engine has a remote/local input as well as a throttle select (gen/prop) input. As such, each engine has a selected Desired Speed Source, also known as the Desired Throttle Input. The messages indicating the selected Desired Speed Source are communicated via CDL at the following addresses:
Engine 1 Desired Throttle Input: $D1 $0024
Engine 2 Desired Throttle Input: $D1 $0025In some cases, the selected Desired Speed Source is not the same as the actual Desired Speed Source that is currently being used to control the engine. This may be due to such things as Desired Speed Source Change Inhibits or conditions related to coupling. To give an indication of the actual Desired Speed Source, also known as the Actual Throttle Input, each engine has a message at the following addresses:
Engine 1 Actual Throttle Input: $D1 $0026
Engine 2 Actual Throttle Input: $D1 $0027Relays
Illustration 3 g03282356
Dry Contact Relays for Local/Remote StatusA set of dry contacts is provided on the panel to indicate the local or remote status of each engine. The dry contacts are shown in Illustration 3 with the corresponding terminal block labels.Failure Modes
Tables 3, 4, 5, and 6 describe what happens during each of the Desired Engine Speed controls failures. Refer to the "CDL Diagnostics and Codes" section of the, "Diagnostic Codes" chapter of this manual for error codes corresponding to these failures.
Table 3
Speed Source Fail Mode (Coupled, Engine 1 Master)    
   If Source 1 Fails, Is Source 1 in Control?    
Source 1    Yes (diagnostic and )    No    
Generator     use Propulsion 1 for control     diagnostic only    
Propulsion 1     use Propulsion 2 for control     diagnostic only    
Propulsion 2     engines go to low idle     diagnostic only