What is the difference between setting limits and setting the target torque on torque meters?
How do I set the limits?
On the TTS-1000 you have the option to set two types of pass/fail "zones". When the peak or first peak is under the "zone" you get a yellow light. When the peak or first peak is within the "zone" you get a green light, when over the "zone" you get a red light. You can set the zone limits (actual high and low values) or you can set a target torque with a percentage, the meter will then calculate the high and low limits based on that percentage. You have to set the meter to the desired method under the setup function.
For example, if you are testing a torque wrench at 100 ft.lb. and the wrench is to be certified to 4% the pass fail tolerance is 96 ft.lb. to 104 ft.lb.. If you use the limits method (select limits in the menu system on the TTS-1000) you will be prompted to enter the actual high and low values as prompted by the arrows pointing up and down on the display (you must calculate those values and enter them).
If you have chosen the target and % method (under set-up) you will be prompted to enter one target value (100.0) and the meter will automatically calculate the pass zone by applying the default percentage you have programmed during set-up. The target % is set as a default value in the set-up of the meter when you select the limits or target method.
HOW TO SET THE METER TO EITHER LIMITS OR TARGET:
NOTE: This procedure is usually done only once when you first set the meter to your preference.
1.Turn the meter on with a transducer attached.
2. Enter the Setup menu by pressing the mode and units key at the same time (Setup will show on the display)
3. Press the > (next) key until the display shows "Tolerance".
4. Press the save key.
5. The display will now show either % On (target with % mode) or two arrows (limits mode).
6. Press the next key to toggle between the type of method you want to use then press the save key.
If you chose the % method you will then be prompted to enter the default % value. This is the value that the meter will use to calculate the pass zone.
The flashing digit is the digit that can be changed with the increase key (+ key). Use the next key to select the second digit, then change the value with the increase key. Press save when done.
After pressing save you will go back into the operation mode.
If you selected "% On" go to step 7. If you selected the up and down arrows (limits) go to step 10.
7. Press the limits on/off key. You will see the percent sign, the default percent value and the current target value (target should be zero on the first use).
8. To set the desired target value press and hold the limits key.
9. Use the increase and next key to set the desired target value. For example set 0100 for 100. The current torque units that are set on the meter are the active units.
Once the value is set you can quickly set a new target torque value by pressing and holding the limits key and the increase and next keys to set the new value.
10. If you chose the limits function instead of the % function the meter will prompt you for the actual low limit (shown by a down arrow) and the actual high limit (shown by the up arrow) after holding the limits key.
11. Press and hold the limits key and the display will prompt you for the low limit setting. Enter the low limit with the increase and next keys. Press Save when the value is correct.
12. Now enter the high limit using the increase and next keys. Press save when the value is correct.
13. Now you will see the actual high and low limits on the display (to the right of the main torque display) when using the limits function.
You will find that the quickest method is to use the target and % system. This way you only need to enter one value (the same value as the tool you are testing is set to). Make sure the % default is set to the proper number (4% for most click wrenches).