BENDIX TABS-6 User Manual

3
3. ANTILOCK BRAKE SYSTEM
(ABS) OPERATION
The Bendix
®
TABS‑6
™
Adv MC module uses wheel speed
sensors,modulatorrelayvalves(MRVs);andanECUto
optimize the contact between the tires and the road surface
during a braking event where excessive wheel slip — or
wheel lock‑up — is detected.
When a situation is detected where the system needs
to intervene, the ECU will activate the MRVs to apply
controlledbrakepressureatthewheelends.Dependingon
thecongurationoftheABSsystem,interventionsmaybe
made on individual wheels, or pairs of wheels. In the case
of pairs of wheels, the wheels controlled by a modulator
may be either on the same side of the vehicle, or at both
ends of an axle.
TheTABS-6AdvMCmoduleECUisabletomodulatethe
brake pressure with greater speed and accuracy than a
driver.
Normal Braking
During normal braking the TABS-6Adv MC module
functionsasastandardrelayvalve.IftheECUdoesnot
detect excessive wheel slip, it will not activate the ABS
system, and the vehicle will stop with normal braking.
Side Control (Independent Control)
Side control uses a single modulator relay valve to sepa‑
rately control the braking on one or more wheels, on each
side of the vehicle.
In the case of braking surfaces with poor overall traction,
the side control ABS interventions will maintain the wheels
on each side of the vehicle independently, at just under the
speed where they would lock up.
Axle Control
Axle control uses a single modulator relay valve to control
the wheels at both ends of a given axle (or multiple axles
in cases where a single MRV is controlling several axles).
In the case of braking surfaces with poor overall traction
(e.g. roads that are worn, slippery, or are made of loose
gravel) — or braking surfaces with areas of poor traction
(e.g. asphalt roads with patches of ice) — axle control ABS
interventions will maintain the wheel that is not slipping at
just under the speed that will lock the wheel. The system
permits the other wheel (that is experiencing slippage)
temporary periods of wheel‑lock during the intervention.
Axle control should not be used on 5th wheel dollies or
steerable axles.
When intervening on regular traction road surfaces, a
systemcongured for axle control performs similar toa
side control, two‑modulator system.
ABS Fail‑Safe
The Bendix
®
TABS‑6
™
Adv MC module is designed to react
inafail-safemannerintheeventofasystemDiagnostic
TroubleCode(DTC).Forexample,iftheECUdetectsthat
asensorisnotresponding,anABSsystemDTCwillbeset
and the TABS‑6 Adv MC module will illuminate the trailer
ABS indicator lamp and revert to a fail‑safe mode where
some, or all, Advanced ABS functions (including TRSP)
maynotfunction.EvenincaseswheretheABSsystem
is completely disabled, the standard pneumatic brake
function of the vehicle will still be available, but without the
benetsofABS.TheTRSPfeatureisalsodisabledwithan
active ABS system diagnostic code. If the indicator lamp
is illuminated, always have the ABS system serviced at the
earliest opportunity.
1
21
22
22
21
21
42
22
1/2" NPT Supply
Port 1
Two 3/8" NPT Delivery
Ports 22
(To Brake Chambers)
Two 3/8" NPT Delivery
Ports 21
(To Brake Chambers)
3/8" NPT Control Port
with Integral Filter
3/8" NPT Load Port 42
For Air Suspension
(Plugged for Non-Air Suspension or
Spring Suspension Sensor Vehicles)
3/8" NPT Delivery
Port 21
(to Brake Chambers)
3/8" NPT Delivery
Port 22
(to Brake Chambers)
FIGURE 2 ‑ PORTS USED

BENDIX TABS-6 Specifications

General

Type	Trailer ABS Module
Operating Temperature Range	-40°C to +85°C
Protection Rating	IP67
Category	Automobile Accessories
Voltage	12V/24V
Communication	J1587/J1939
Mounting	Frame Mount
Manufacturer	BENDIX
System Type	ABS
Number of Channels	4S/2M