FMS Tell Tale Status

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FMS Tell Tale Status Introduction

Tell Tale was created in order to receive all available dashboard indication events that are available on truck via FMS protocol according to J1939 standard. SAE J1939 is the vehicle bus standard used for communication and diagnostics among vehicle components. Based on the same architecture FMS protocol dedicated to telematics systems is available. It has certain standardized parameters available, such as fuel consumption, engine work-hours, etc. Please visit http://www.fms-standard.com/ for more information and message structure.

Is there any Tell Tale parameters available ony my vehicle?

To check if any Tell Tale parameters are available via FMS on your vehicle scanfms SMS/GPRS command can be used. If there is any parameters available on FMS this means that Tell Tale status is available as well. Response will show parameters that are available on vehicle, but it does not include all Tell Tale statuses - only MIL indication is implemented see FMS elements. How to parse scanfms response can be found in wiki FMB_scanfms page.

What parameters should be enabled

FMBX640 have CAN1 and CAN2 BUS lines that are already configured.

FMB640 CAN1 connected to vehicle's FMS(J1939) BUS line
FMB640 CAN2 connected to vehicle's Tachograph

More information in CAN\Tachograph paragraph

Configurable parameters via SMS/GPRS commands can be found at FMB640_Device_Family_Parameter_list#FMS

How does it work?

IO element describes Tell Tale Block ID message received from Block ID 0,1,2,3 in Hexadecimal format.:

Tell Tale ID0
Tell Tale ID1
Tell Tale ID2
Tell Tale ID3

Each ID represents Block ID of Tell Tale.

IO elements store information that is received from FMS Tell Tale Status message (CAN ID - 0x00FD7D).
Status message sends Data Block information in Data Byte 1. Block ID is determined by Data Byte 1 first 4 Bits. Example in hexadecimal first 4 bits where X – random byte value.

X0₁₆ – Block ID 0 - FMS IO element Tell Tale ID0
X1₁₆ – Block ID 1 - FMS IO element Tell Tale ID1
X2₁₆ – Block ID 2 - FMS IO element Tell Tale ID2
X3₁₆ – Block ID 3 - FMS IO element Tell Tale ID3

Once Block ID is captured all 8 bytes of Tell Tale message are saved to corresponding Tell Tale IO element.

Example of FMS Tell Tale status data:

When device is powered up all elements are be updated to the first corresponding message.

After 4 seconds (1000 ms per Block ID) all values will be captured again. Device checks last saved value of Tell Tale IO elements and if it is changed – values are updated.

How to parse Tell Tale message

Bytes should be read from Right <<< To left.
4th and 8th Bytes are not defined

Statuses are described in FMS document.
See Table for Tell Tale statuses, page 27 (60)
Binary table to determine indication status can be found in 1.1.16 FMS Tell Tale Status: FMS1, Page 26 (60)

Received data:

Block ID = 0| 0xFF8F88FFBFFFFFF0

Block ID = 1| 0xFFFFFFFFFFFF8FF1

Block ID = 2| 0xFFFF8FFFFFF8FFF2
Block ID = 3| 0xFFFFFFFFFFFFFFF3

Quick links

FMS-Standard Description Document

Tell Tale only available on vehicles that support FMS standard

Tell Tale examples are provided in FMS-Standard Description document that is publicly available

Availability of parameter depends on vehicle’s model and configuration of the FMS interface of the truck.

Note: FMS Tell Tale status is supported on FMB640 FMC640 FMM640 FMB630 FM6300 devices. Also please check firmware errata table to see from which firmware version this feature is available.