Calibrating UM-Sensor Box in the Field

This document shows how to calibrate the UM-Sensor module.

Note - If you see upper and lower case letters specified here, please use them!
Some commands are case-sensitive, while others are not. This document uses the command syntax just as it appears in the UM-Sensor Specification 6 759 269 ZW revision F.

In this document, we will cover eight commands:

Ya 0 -- to select Celsius temperature units.
Ya 1 -- to select Fahrenheit temperature units.
Yb -- to read ambient humidity.
Yb <number> -- to SET the Relative Humidity.
Yq -- to read UM-Sensor diagnostic status (0=OK, 1-255 = problem detected)
Ys -- to read contact input status (1=ON, 0=OFF, left-most bit is for contact 8)
Yt -- to read the temperature.
Yt <number> -- to SET the temperature.

Tools Required

1.    You need a straight-through 9 pin serial cable with one male and one female end on it. An MGE Windows cable (P/N 66049) will also work. All that is required is that pins 2, 3, and 5 are a "straight through" connection.

2.    You need a computer running Windows 95 or Windows 98, with Hilgraeve HyperTerm installed.

Establishing Communications

3.    Connect the communications cable to Com 1 on the computer and to the "IN" port on the back of the UM-Sensor box.

4.    Power up the UM-Sensor box by attaching the power block to a 120 VAC outlet.

5.    Start HyperTerm on the PC. Cancel the Connection Description window. Click on Properties.

6.    Set up a session with the following properties:

Direct to Com 1

Click the Configure button…
2400 Baud
8 bits, No parity, 1 stop bit
No flow control

Click on Advanced…
Use FIFO Buffers (can be ON or OFF)

Click on OK twice

Click on Settings tab…
Terminal keys
Backspace key sends Ctrl+H,Space,Ctrl+H
Emulation can be set to Auto Detect

Click on ASCII Setup button…
Send line ends with line feeds
Echo typed characters locally
Wrap lines that exceed terminal width

Click on OK twice. You should be in HyperTerm's main screen.
Click on File, Save As…, then type a name for the connection (Example: UM-Sensor)
Click on Save. You should be back at HyperTerm's main screen.

7.    Click on the phone icon to establish a connection. Verify that the word "Connected" shows up on the bottom status line.

Note: Some commands are case-sensitive, and some are not. It is not the intent of this document to "discover" which ones work and which ones really are case-sensitive, so be sure to type each command as it appears in the text in this document. If the command is not understood by UM-Sensor, it will echo back a question mark (?) as the answer.

Checking for a Healthy UM-Sensor

8.    Enter the command, Yq and press Enter. This asks UM-Sensor to perform a self-test. If you get any number between 1 and 255, there is a problem. If answer is 0 (zero), then no problems are detected.

Check Temp and Humidity

9.    Enter the command, Yt and press Enter. This will display the current temperature.
10.    Enter the command, Yb and press Enter. This will display the current humidity.

Set Temp and Humidity

11.    To change Temperature (default is in degrees Celsius), enter the temperature command, a space, and a number that will be the current temperature, then press Enter. Example: Yt 23 (This command will set the current temperature to 23 degrees Celsius). If you have UM-Sensor configured for temperature in degrees Fahrenheit, enter the same command but use the current number for the temperature in degrees F.
12.    To change Humidity, enter the humidity command, a space, and the number that represents the current relative humidity in percent, then press Enter. Example: Yb 38 (This command will set the current relative humidity to 38%).

Selecting Temp Scale

Note: We found that you can select whether the temperature is sent in Celsius or Fahrenheit by setting the proper mode. But there's a problem --- the Console+ program displays the correct number of the temperature in degrees, but it always displays that number on a Celsius scale! This is a function of Console+, and there is no way to get a Fahrenheit display for the moment. So we must use Celsius for now.

13.    To select the Celsius temperature scale, enter the command, Ya 0 and press Enter. The response is "OK", which means that the command was accepted. A response of "NOK" means the command was rejected. To check what the temperature is, enter the command, Yt and press Enter. The response will be the temperature in degrees Celsius.
14.    To select the Fahrenheit temperature scale, enter the command, Ya 1 and press Enter. The response should be OK, which means that the command was accepted. To check the current temperature in degrees F, enter the command Yt and press Enter. The response will be the temperature in degrees F.

Terminal Strip Input Status Command

15.    To read the input status of the 8 terminal bus inputs, enter the command, Ys and press Enter. The response will be an 8 digit number. Each number represents the state of one contact on the terminal bus - either 1 (ON) or 0 (OFF). The number on the left end (Most Significant Bit, or MSB) represents terminal #8, and the number on the right end (Least Significant Bit, or LSB) represents terminal #1. Note that when viewing the terminal strip on the back of UM-Sensor, the terminals are numbered from right to left - backwards of how you would expect to see them. This gives you the advantage of seeing the terminals in the same order as the input status number that is displayed on the screen.

That's all there is to it! Your UM-Sensor is properly calibrated.