Detcon PI-500 - Manual (Page 29)

To adjust the display contrast, remove the enclosure cover and use a jewelers screwdriver to turn the contrast adjust screw
located beneath the metallic face plate. The adjustment location is marked “CONTRAST”. See f igure 6 for location.
3.12 U NIVERSAL T RANSMITTER F EATURE (R E -I NITIALIZATION )
The Model PI-500 uses a universal transmitter design that allows the transmitter to be set up for any target gas and any
toxic concentration range. The original transmitter set-up is done at Detcon Inc. as part of the sensor test and calibra-
tion procedure, but it may also be changed in the f ield if necessary. The Universal Transmitter feature is a signif icant
convenience to the user because it allows hardware f lexibility and minimizes the spare parts requirements to handle
unexpected transmitter failures of different gas/ranges. It is however, absolutely critical that changes to gas/range set-up
of the Universal Transmitter be consistent with the gas type and range of the PID Sensor Head that it is connected to.
The PID sensor head will display the range it is set up for, based on the isobutylene reference calibration.
NOTE: If the Universal Transmitter is changed for gas type and range, it must be consistent with the PID sensor head
it is mated with.
If the Universal Transmitter needs to be changed for gas type and range follow this procedure. First, unplug the trans-
mitter temporarily and then plug it back in. While the message “Universal Transmitter” appears, take the program mag-
net and swipe it over magnet PGM1. This will reveal the set-up options for gas range and gas type.
Swipe over PGM1to advance through the options for gas range which include:
1, 2, 3….10 ppm
10, 15, 20……100 ppm
100, 200, 300…..1000 ppm
1000, 2000, 3000 …..10,000 ppm
When the correct range is displayed, hold magnet over PGM1 for 3 seconds to accept the selection.
Next is your selection for the gas type that will be displayed. Note, the default gas is “VOC”. In this set-up you will
enter the alpha-numeric characters of the gas type. There is space for the chemical formula name of up to six characters.
Use PGM1 and PGM2 swipes to advance through the alphabet and numbers 0-9 selection (there is a blank space after
9). When the correct alphanumeric character is highlighted, hold the magnet over PGM1 for 3 seconds to lock it in.
This moves you to the next blank and the procedure is repeated until the chemical formula is completed. After the 6th
character is locked in the transmitter will proceed to normal operation.
NOTE 1: If the gas symbol has more than 6 characters, the symbol can be replaced by an abbreviated version of the
target gas name such as TOL or TOLUEN for Toluene which has a the symbol C6H5CH3. For epichlorohydrin (sym-
bol C3H5OCL) you can substitute the name EPI or EPICHL etc.
NOTE 2: When the Universal Transmitter is re-initialized and a new gas and range is entered, the previous customer
settings for span gas value, response factor, and zero offset are reset to default levels. This must be re-programmed back
to the customer specif ic settings.
3.13 T
ROUBLE
S
HOOTING
Sensor reads Over-range after Power-up
Probable Cause: Sensor requiring additional stabilization time, VOC gases present in background air, Improper zero or
span calibration.
1. Verify that there is not large amounts of target gas or interfering gases in background.
2. Redo zero and span calibrations.
3. Make sure transmitter range is consistent with PID sensor head range.
Reading Higher than Anticipated
Probable Causes: Target or Interfering gases in background, Incorrect calibration for Zero or Span.
1. Verify no target or interfering gases are present. If so, use the Zero Offset feature.
2. Redo Zero and Span calibrations with validated Zero Gas and Span Gas standards.
PI-500 Toxic Gas Sensors PG.29