Desco EMIT 500524 User manual

TB-6542 Page 1 of 5 Revision 10/04
50524 Limit Comparator
CALIBRATION CHECK
RESISTOR BOX
OPERATING INSTRUCTIONS
3651 Walnut Avenue, Chino, CA 91710
Phone: [phone]
Fax [phone]
www.descoemit.com

TB-6542 Page 2 of 5 Revision 10/04
50524
Limit Comparator
Calibration for models 50522 and 50528 OPERATOR
CALIBRATION CHECK RESISTOR BOX
OPERATING INSTRUCTIONS
1. The purpose of the DUAL WIRE Limit Comparator Operator Calibration Check
Resistor Box is to verify the calibration of the ZVM 50528 and the 50522 by
checking 4 operator conditions: FAIL LOW, PASS SAFE (low limit), PASS SAFE
(high limit), and FAIL HIGH.
2. There are 10 resistor settings on the resistor box, which can be set using the
rotary switch. Positions 3 through 8 have installed values. Positions 1, 2, 9, and
10 can be installed by the user for one set each of custom low and high limits.
The standard settings are as follows:
POSITION:
1.) optional low limit fail low
2.) optional low limit pass safe
------------------------------
3.) 1.91 MΩFAIL LOW
4.) 1.91 MΩPASS SAFE (ZVM default settings)
5.) 10 MΩPASS SAFE
6.) 10 MΩFAIL HIGH
------------------------------
7.) 35 MΩPASS SAFE
8.) 35 MΩFAIL HIGH
9.) optional high limit pass safe
10.) optional high limit fail high
PLEASE NOTE THAT THE ZVM OPERATOR CALIBRATION CHECK RESISTOR
BOX IS USED TO CHECK ONE OPERATOR AT A TIME.
3. Ensure that the ZVM to be checked is set up as described in the operating
instructions and has power.
4. Connect the plug from the resistor box into the OPERATOR 1 remote jack.

TB-6542 Page 3 of 5 Revision 10/04
5. Turn the rotary knob on the resistor box to “x ΩLOW” (select x = 1.91MΩor the
optional low limit fail low, according to what operator low limit the ZVM is
calibrated at). Observe the operator 1 LED display on the front of the ZVM. The
yellow LED should be lighted and the audible alarm should sound, indicating the
fail low condition.
6. Turn the rotary knob on the resistor box to “x ΩSAFE” (select x = 1.91MΩor the
optional low limit pass safe, according to what operator low limit the ZVM is
calibrated at). The green LED on the ZVM operator 1 display should be on,
indicating the low limit pass safe condition.
7. Turn the rotary knob on the resistor box to “x MΩSAFE” (select x = 10MΩ, 35MΩ
or the optional high limit pass safe, according to what operator high limit the ZVM
is calibrated at). The green LED on the ZVM operator 1 display should be on,
indicating the high limit pass safe condition.
8. Turn the rotary knob on the resistor box to “x MΩHIGH” (select x = 10MΩ,
35MΩor optional high limit fail high, according to what operator high limit the
ZVM or is calibrated at). The red LED on the ZVM operator 1 display should be
on and the audible alarm should sound, indicating the fail high condition.
9. Disconnect the resistor box plug from the operator 1 remote jack. Plug the
resistor box plug into the operator 2 remote jack and repeat the four tests in
steps 5 through 8 to test operator 2.
10.The correct color LED's must light for each step for the ZVM to completely pass
the calibration check. If an incorrect LED comes on during any portion of the test
(example: expecting the green LED to light in step 7 but the ZVM red LED is on)
recalibrate the ZVM with the ZVM-PRG (making certain that the correct
calibration resistances are installed in the ZVM-PRG and the correct procedures
are followed for that unit) and test each operator again with the EN445-ZVM cal
check resistor box.
INSTALLING OPTIONAL LOW AND HIGH LIMIT RESISTANCES
A.) Use a hex wrench to remove the rotary switch knob. Unscrew the 2 screws on the
back of the unit and disassemble the unit.
B.) Two resistances must be installed for each limit: one for PASS SAFE and another
for FAIL. These two resistances should be ±10% of the calibrating resistance. For
example:

TB-6542 Page 4 of 5 Revision 10/04
LOW LIMIT
CALIBRATION
RESISTANCE
LOW LIMIT FAIL LOW
RESISTANCE
[1M - (1M x 10%)]
LOW LIMIT PASS
SAFE RESISTANCE
[1M + (1M x 10%)]
1MΩ900KΩ1.1MΩ
HIGH LIMIT
CALIBRATION
RESISTANCE
HIGH LIMIT PASS SAFE
RESISTANCE
[15MΩ- (15MΩx 10%)]
HIGH LIMIT FAIL HIGH
RESISTANCE
[15MΩ+ (15MΩx 10%)]
15MΩ13.5MΩ16.5MΩ
C.) The table below specifies which numbered resistances on the circuit board
correspond to the optional low limit and the optional high limit. Solder the appropriate
resistors in these places.
Optional low limit Designated resistors on
circuit board
Low limit fail low R1, R1A (*connected in
series)
Low limit pass safe R2, R2A (*connected in
series)
Optional high limit Designated resistors on circuit
board
High limit pass safe R9, R9A (*connected in series)
High limit fail high R10, R10A, R10B (*connected in
series)
NOTE: Two (three for position 10) resistor locations are connected in series are
provided in case resistors need to be added to achieve the desired total resistance.
Solder a shorting wire across the resistor locations that are not used.
D.) Assemble the unit and mark the appropriate places on the label for the optional
limits.
E.) It is recommended to turn the rotary switch to the optional positions and measure
the resistance from the tip to the body of the plug with an ohmmeter to verify the
resistances.
ohmmeter
MAINTENANCE: Wipe the plug periodically with alcohol.

TB-6542 Page 5 of 5 Revision 10/04
TECHNICAL SUPPORT:
USA Europe
Desco EMIT Charleswater
3651 Walnut Avenue Unit 17, Millbrook Business Park, Sybron Way
Chino, CA 91710 Crowborough, East Sussex, TN6 3JZ, U.K.
Tel: [phone] Tel: [phone]
Fax: [phone] Fax: [phone]
NOTE: Unauthorized servicing or modifications to your monitor will void the product
warranty and may create dangerous conditions. Servicing should be performed only at
the factory, or by a Desco EMIT approved technician.
LIMITED WARRANTY
Desco Emit expressly warrants that for a period of one (1) year from the date of purchase,
Desco Emit 50524 will be free of defects in material (parts) and workmanship (labor). Within the
warranty period, a unit will be tested, repaired, or replaced at our option, free of charge. Call
Customer Service at 909-627-8178 (Chino, CA) or 01892 665313 (Crowborough, U.K.) for
Return Material Authorization (RMA) and proper shipping instructions and address. Include a
copy of your original packing slip, invoice, or other proof of date of purchase. Any unit under
warranty should be shipped prepaid to the Desco EMIT factory. Warranty replacements will
take approximately two weeks.
If your unit is out of warranty, Desco EMIT will quote repair charges necessary to bring your unit
up to factory standards. Call Customer Service at 909-627-8178 for proper shipping instructions
and address. Ship your unit freight prepaid.
WARRANTY EXCLUSIONS
THE FOREGOING EXPRESS WARRANTY IS MADE IN LIEU OF ALL OTHER PRODUCT
WARRANTIES, EXPRESSED AND IMPLIED, INCLUDING MERCHANTABILITY AND
FITNESS FOR A PARTICULAR PURPOSE WHICH ARE SPECIFICALLY DISCLAIMED. The
express warranty will not apply to defects or damage due to accidents, neglect, misuse,
alterations, operator error, or failure to properly maintain, clean or repair products.
LIMIT OF LIABILITY
In no event will Desco EMIT or any seller be responsible or liable for any injury, loss or damage,
direct or consequential, arising out of the use of or the inability to use the product. Before using,
users shall determine the suitability of the product for their intended use, and users assume all
risk and liability whatsoever in connection therewith.