CTS T-40/50 — Environmental Chamber¶

Overview¶

The CTS T-40/50 is an environmental test chamber for temperature and humidity testing. It uses a proprietary binary ASCII protocol over RS-232 — not VISA/SCPI.

Specification	Value
Type	Environmental Test Chamber
Temperature range	−75 … +185 °C
Interface	RS-232 (COM port), 19200 baud, 8N1 with odd parity
Protocol	Custom binary ASCII framing (STX / ADR / DATA / CHK / ETX)
Driver name	`CTSChamber`
Resource patterns	`COM?*`

Serial Connection Settings¶

The CTS chamber does not use VISA. The driver uses a custom IConnectionProvider that opens a COM port directly:

Parameter	Value
Baud rate	19200
Data bits	8
Parity	Odd
Stop bits	1
Flow control	None

Connecting¶

Connect the CTS chamber's RS-232 port to the PC (use a USB-to-RS232 adapter if needed)
Note the COM port number from Device Manager
Click Add Instrument and select the COM port resource (e.g. COM3)
The Connection Manager lists COM ports automatically
Select the CTSChamber driver from the drop-down (auto-detection is not possible because the chamber does not respond to *IDN?)
Click Connect

USB-to-RS232 adapters

Use a high-quality adapter with a genuine FTDI or Prolific chip. Cheap adapters often lose data at 19200 baud with odd parity.

Protocol Details¶

The CTS chamber uses a proprietary binary ASCII framing scheme. Developers who need to extend the driver should read the CTSSerialConnectionProvider documentation.

Frame structure:

STX  |  ADR  |  DATA (each byte OR'd with 0x80)  |  CHK  |  ETX
0x02    0x30    0xC2 0xD4 ...                        0xHH   0x03

The checksum (CHK) is the XOR of all bytes from ADR to the last DATA byte.

Front Panel¶

Control	Description
Set Temperature (°C)	Target temperature
Set Ramp (°C/min)	Temperature ramp rate
Start	Start the chamber program
Stop	Stop the chamber
Pause	Pause the current program
Temperature readback	Current chamber temperature in °C
Status	Chamber operating mode (Running, Paused, Idle, Error)

Sequence Blocks¶

CTSChamber_SetTemperature¶

Sets the target temperature set-point.

Property	Type	Description
Instrument	InstrumentSelector	Connected CTS chamber instance
Temperature (°C)	Number	Target temperature

CTSChamber_SetRamp¶

Sets the ramp rate between temperature set-points.

Property	Type	Description
Instrument	InstrumentSelector	Connected CTS chamber instance
Ramp Rate (°C/min)	Number	Rate of temperature change

CTSChamber_Start¶

Starts the chamber conditioning program.

Property	Type	Description
Instrument	InstrumentSelector	Connected CTS chamber instance

CTSChamber_Stop¶

Stops the chamber and returns to standby.

Property	Type	Description
Instrument	InstrumentSelector	Connected CTS chamber instance

CTSChamber_Pause¶

Pauses the current program without losing the set-point.

Property	Type	Description
Instrument	InstrumentSelector	Connected CTS chamber instance

CTSChamber_ReadTemperature¶

Reads the current chamber temperature.

Property	Type	Description
Instrument	InstrumentSelector	Connected CTS chamber instance
Variable	Variable	Receives temperature in °C

CTSChamber_WaitForTemperature¶

Blocks execution until the chamber reaches a temperature within a tolerance band, or a timeout expires.

Property	Type	Description
Instrument	InstrumentSelector	Connected CTS chamber instance
Target (°C)	Number	Target temperature
Tolerance (°C)	Number	Acceptable deviation band (e.g. `0.5` means ±0.5 °C)
Timeout (s)	Number	Maximum wait time in seconds. 0 = no timeout.

Example Sequence — Temperature Profile Test¶

[Start]
→ [CTSChamber_SetRamp, Rate=2.0]
→ [CTSChamber_Start]
→ [Loop temperatures in -40, 25, 85°C: use SetVariable]
    ↓
    [SetVariable, Name=targetTemp, Value=-40]
    → [CTSChamber_SetTemperature, Temp={targetTemp}]
    → [CTSChamber_WaitForTemperature, Target={targetTemp}, Tolerance=0.5, Timeout=3600]
    → [Wait 300000ms]   # soak 5 minutes
    → [HP34401A_MeasureDCV, Variable=voltage]
    → [SaveCsv, Path="C:\Data\temp_profile.csv", Append=true]
→ [CTSChamber_Stop]
→ [End]