What is OptiSet?
It is a group of programmable functions found in the ΅P-VI or SR2 microprocessor controller. This is the standard controller on SB-190, SB-200 & SB-300 units. OptiSet provides complete control over how the unit will operate with a specific setpoint. A trailer may be used to transport different types of products. Each of these products may have different setpoint, air flow and temperature tolerance requirements.

In the past, the driver decided the best operating mode for the load and the unit. This was often done without a complete understanding of load requirements. Sometimes this caused product quality problems or in-efficient use of the unit.

OptiSet allows unit operation and product quality decisions to be made in advance. You and the fleet manager are able to setup what the Thermo King unit will do when a set point is chosen. This assures that when a particular setpoint is selected, the unit will always operate the same way. At a different setpoint it will always operate in a particular, but different, way. Therefore, no guess work by the driver resulting in more consistent product quality and more efficient use of the unit.

Operating Modes
OptiSet controls several operating modes. They may be used in up to 10 different combinations with different programmable settings. Each of these combinations is connected to a setpoint range. The four operating modes that are controlled by OptiSet are:


2. Continuous Run

3. Modulation

4. Economy

Each of these modes will have settings and functions specific to that mode.

This is Start / Stop operation. It is based on setpoint and return air temperature. CYCLE-SENTRY allows the unit engine to shutdown when return air temperature has reached setpoint. Because the engine is not consuming fuel or accumulating engine hours, it is saving money.

During the off cycle, or NULL, no air is moving in the trailer. Some products, such as fresh produce, require constant airflow. CYCLE-SENTRY is not recommended for these loads.

Some types of products can be transported using CYCLE-SENTRY. These would include anything frozen or products packaged in some kind of airtight container. Frozen vegetables, packaged fresh meat and dairy products are good examples.

CYCLE-SENTRY mode can be turned ON or OFF by OptiSet within a setpoint range.

Continuous Run Mode
In this mode the unit runs all of the time. It continues to burn fuel and accumulate engine hours. The air inside of the trailer is always moving. This is good for fresh produce. To maintain product quality the unit must operate in continuous run. There is a trade off between economy and product quality.

Continuous Run mode can be turned ON or OFF by OptiSet within a setpoint range.

Modulation Mode
The SB-200 & 300 contain an Electronic Throttling Valve (ETV) as standard equipment, optional on SB-190. Use of the ETV and the modulation mode allow very precise temperature control. This mode provides constant airflow in the trailer by operating in continuous run. It is available in the fresh range only. Product quality is improved by eliminating “top freeze” and reducing dehydration.

During modulation mode, the ΅P-VI controller monitors return or discharge air temperature. It controls the ETV, which restricts the suction line to reduce refrigeration capacity to just enough to maintain temperature.

Modulation mode can be turned ON or OFF by OptiSet when the setpoint is in the fresh range and operating in continuous run.

Economy Mode
Economy is a new mode with OptiSet. It is designed to increase fuel economy in both CYCLE-SENTRY and continuous run.

During CYCLE-SENTRY mode, OptiSet will control the following settings.

1. NLRS, Null Range Setting expands the temperature range between setpoint and restart. This helps keep the engine off longer.

2. FSII, the Fuel Saver II timer prevents high speed operation for 8 minutes after a CYCLE-SENTRY start. This keeps the engine in low speed as much as possible.

3. HSPD, High Speed Pull-down is supposed to get the load to setpoint quickly so the unit can shut down sooner.

4. MNTL, Maximum Null Time Limit will cause the unit to start independently of box temperature demand. Based on a timer that periodically starts the unit just to move air inside of the trailer.

5. MOTL, Minimum Off Time Limit will not allow the unit to restart until a minimum amount of time has passed. Eliminates short cycle restarts and helps keep the engine off more.

During Continuous Run mode, OptiSet will control the following settings.

1.FSII, Fuel Saver II delays high engine speed for 8 minutes after the controller has a high speed demand. This keeps the engine in low speed as much as possible.

2. HSPD, High Speed Pull-down is supposed to get the load to setpoint quickly so the load temperature is more stable and the unit spends more time in low speed.

3. LSSP, Low Speed Switch Point expands the low speed temperature range. This keeps the engine in low speed as much as possible.

Range Selection
OptiSet allows you to program up to 10 operating temperature ranges. You do not need to use that many. It depends on your customers needs. Perhaps 3 or 4 ranges are enough.

A new unit comes with 2 ranges programmed. The first range is from –20 F to 24 F, frozen range. The second range is from 25 F to 80 F, fresh range. All modes are selectable and programmed to default settings.

To do a custom setup you will build temperature ranges from –20 F up to 80 F. The ranges are numbered from 0 to 9. Each range builds on the one below it. For example, range 0 might be from –20 F up to 0 F. Range 1 would start at 1 F and stop at 24 F. Range 2 would start at 25 F and might stop at 45 F. Range 3 would start at 46 F and stop at 80 F. Each one of these setpoint ranges can have different settings. The ranges must break at the fresh/frozen point (FRFZ), typically 24 F.