OHMIC INSTRUMENTS AMM-15 Air Line Moisture Monitor Instruction Manual

Ohmic Instruments
3081 Elm Point Industrial Drive St. Charles, MO 63301 USA
Phone 410-820-5111
Toll Free(800) 626-7713
Fax 410-822-9633

www.ohmicinstruments.com
Sales: sales@ohmicinstruments.com
Service: service@ohmicinstruments.com

AMM-15 Manual
AIR-LINE MOISTURE MONITOR
Model AMM-15

© Ohmic Instruments
2021

All rights reserved. This manual may not be reproduced in complete form without written permission of Ohmic Instruments. Individual pages may be copied as required by the original purchaser of the instrument. Information contained  in this manual is believed to be accurate and reliable; however, no responsibility is assumed by Ohmic Instruments for its use. Ohmic reserves the right to supply its instruments with design changes and/or component substitutions that  may not be documented in this manual.

* Storage recommendations:

To prevent damage to the unit or changes to the sensor elements the unit should be stored at 0 to 125 Deg. F. at less than 90 % RH. Long term storage of the AMM-15 out of these conditions is not recommended by Ohmic Instruments.
We also recommend removing the batteries if the unit will not be used for an extended period.

INTRODUCTION

Ohmic Model AMM-15 Air-line Moisture Monitor is a portable hand -held instrument designed to accurately monitor the dew point and dry -bulb temperatures in compressed air lines as well as low pressure systems. The unit is Microprocessor-based and is powered by four size-AA alkaline batteries or by the enclosed AC Adapter. Four frontpanel keypad switches provide power on, power off, choice of Dewpoint / dry-bulb temperature display, and choice of °F / °C units. The display is a 3-½ digit LCD with 0.5″ digit height. The AMM-15 determines the dew point temperature from measurements of humidity and dry- bulb temperature of the sample air from the system under test. Dew point is then calculated from these measurements using pre-programmed psychrometric equations and is fully compensated for variations in sample dry-bulb temperature. Connection to system is accomplished via plastic quick disconnects  provided with the unit.
Model AMM-15 is an ideal choice for personnel involved in operating, maintaining, or inspecting compressed air systems  in medical, commercial, and industrialfacilities.

Features of the AMM-15 include:

• Dew point measurement range from -40 to +80 °F
• Durable case with sealed membrane keypad and 3-½ digit display
• Sample compressed air or low pressure systems
• Analog and RS-232 outputs for data transmission
• 32-Kbytes Data Logger memory

SAMPLE MODES/CONNECTING INFORMATION

The AMM-15 is designed for use with both compressed and low pressure air systems, and can accurately measure conditions in air lines operating at pressures from 0 to 120 psi. Two ports are provided for flexibility: free flow mode can be used when the pressure or flow-rate is very low; alternatively, for systems with line pressures above 5 psi, an 0.008″ orifice is provided to maintain controlled flow rates for highest accuracy.

Monitoring Plastic Resin Dryers, Ovens, and Low Pressure Vessels
In low pressure applications (pressure less than 5 psig), use the free-flow mode. This is done by connecting the inlet port to the sample air source using the quick connect fitting provided, making sure that the filter is connected between the unit and the sampled air source. A suggested hook-up diagram of this is on the following page. If there is sufficient pressure and flow, the second sample port can be exhausted to ambient or reconnected to the sample source at a lower pressure point, providing closed-loop monitoring. If necessary where the source pressure is insufficient to provide positive flow, a vacuum pump can be connected to the second sample port to help draw a sample.

Monitoring Compressed Air or Pressurized Vessels
In compressed air applications (above 5 psi), the dew point measurements are made at line, rather than atmospheric pressure, eliminating the need to calculate pressure dew points. The air is vented to ambient through a back pressure orifice installed on the exhaust. Install the exhaust orifice, provided with the AMM-15, in the outlet port. The 0.008″ orifice restricts the exhaust flow with a negligible pressure loss to maintain controlled flow rates for highest accuracy. Connect the inlet port to the air source following the diagram on the next page. Be careful not to connect the AMM-15 to line pressure in free-flow mode; the resulting high flow rate will damage the internal sensors.

Note on High Temperature Applications
For temperatures up to 140°F, the poly tubing supplied with the AMM-15 is sufficient. Air sources above 140°F  and up to 550°F can safely be measuredusing a 6-foot length of ¼” O.D. copper tubing to dissipate the excess heat.
Cooling the sample will not change  thedew point, but will protect the AMM-15 from damage.

AMM-15 CONNECTIONS

OPERATING INSTRUCTIONS

1. Make sure the alkaline batteries have sufficient power. The display will show the low battery symbol if the batteries are inadequate. If the instrument has not been used for a period of time, the batteries should be checked and replaced if necessary. If desired, the AMM-15 can be operated from the AC Adapter (it does not charge the batteries). As with all such equip­ment, if the unit is not to be used for an extended period, the batter­ies should be removed.
2. Purge the air line to be tested of any water, oil, or other foreign matter. The sensors are suscepti­ble to contamination and damage from impurities such as water, oil, dust, chemicals, etc. THE PRO­VIDED FILTER MUST BE BE­TWEEN THE AMM-15 AND THE SYSTEM BEING SAMPLED FROM. FAILURE TO USE THE FILTER VOIDS THE WARRAN­TY. OHMIC INSTRUMENTS IS NOT RESPONSIBLE FOR MIS­USE OR NEGLECT OF THE UNIT.
3. Connect the AMM-15 to the air line following the recommenda­tions on the Sample Modes / Connecting Information page. [AIR LINE PRESSURE IS NOT TO EXCEED 120 PSI]
4. Press the ON button. The AMM­15 always displays Dewpoint on power up. The DP / DB selector button will change the displayed parameter from Dewpoint to Dry Bulb Temperature. The display will show a “down” arrow when displaying Dewpoint and an “up” arrow when displaying Dry Bulb Temperature. The °F / °C selector button will change the displayed parameter from degrees Fahren­heit to degrees Celsius.
5. Allow sufficient time for the read­ings to stabilize. Normal stabiliza­tion will occur within 1 to 1-1/2 minutes. Very low readings, less than -10°F DP, will take up to 10 or 15 minutes for stabilization.

Analog Output

The AMM-15 provides an analog output of 0-1 VDC (from —55 to +95° F Dew Point). Use the enclosed 2-wire plug adapter, and connect a voltmeter to the wires: Red/white to positive (+) and black/white to nega­tive (-). Plug the adapter into the jack marked Analog Out, and see the table on Page 13 for values.

RS-232 INTERFACE- Connect­ing the AMM-15 to your Comput­er

Connecting to a serial port The AMM-15 can be plugged into any S­pin PC serial (COM) port using a S­pin serial cable, available from most computer stores. If your computer has a 25-pin COM port, 25-pin to S­pin serial adapters are also available from most computer stores and can be used with the cable [Serial data is transmitted using Pin 5 (ground), Pin 3 (transmit), and Pin 2 (receive)]. Some computer COM ports and seri­al adapters are not fully implemented (not all pins are used). If the AMM-15 is connected to a partially implement­ed serial port, functions may be errat­ic or the unit may fail to communi­cate. Please consult the owner’s manual for your computer if this oc­curs. Set up your communications program as described on the next page.

Connecting to a USB port If your computer has USB ports you can get an optional RS-232 to USB adapter from Ohmic. Ohmic recommends using an RS-232 to USB adapter only with Windows XP© and Windows Vista ©. Connect the   AMM-15 using the RS-232 adapter and RS-232 to USB adapter. Turn on your computer.
When your computer recognizes the device click OK and follow the instructions for installing the driver software. Set up  your communications program as described below.

LOGGING AND DATA UPLOADING
The AMM-15 can be set to log data at four fixed intervals of 5, 10, 30, and 60 seconds. The factory preset default is 60 seconds, but this can be changed using the DIP switch and chart below.
A maximum of 2860 Dew Point and Temperature readings can be stored. However, once the memory logging space has been filled, a wrap feature of the memory storing causes the oldest data to be overwritten. Thus, when the memory is full, the logger will hold a “sliding window” spanning the 2860 readings.

Uploading the logged data can be done at any point. The stored readings are transmitted chronologically, each line of the display corresponding to one scan of the sensors. For a full logger memory of 2860 readings, uploading takes approximately three minutes. Note, however, that a slow scrolling speed of the terminal screen might stretch this interval to about four and a half minutes.

LOCKED =ON
30| OFF| ON
10| ON| OFF
5| ON| ON

Each AMM-15 ships with DIP switches 1, 2, and 3 off, and 4 on.

SUMMARY OF COMPUTER COMMANDS

The following is a list of commands accepted by the AMM-15. Make sure you read through the notes on Page 10 before attempting to change any of the settings. Each command should be followed by pressing the Enter key.

C| Toggles display of readings  On / Off. Logging always comes on when the unit is powered up using the  keypad ON button.
---|---
S| Transmit current settings of parameters.
SC| Change computer display to Celsius.
SF| Change computer display to Fahrenheit.
TMM DD YY hh mm ss| Set date and time for real time clock:
MM = month  (01–12)
DD = day  (01–31)
YY = year  (00–99)
hh = hours  (00–23)
mm = minutes  (00–59)
ss = seconds  (00–59)
E9090| Clear stored data.
U| Upload stored data. Readings, including a time stamp, are transmitted in chronological order, one line  corresponding to one scan of the sensors.
H| Halt the uploading of data. This command can be used only when uploading is in progress.
When halted, only two commands are accepted:
Q| Terminate the uploading in progress and resume the measurement and logging functions.  This command can be used only following the Halt command (H).
 U| Resume uploading data.  This command can be used only following the Halt command (H).

See the note on the next page if the computer does not display what you are typing.

NOTES ON COMMUNICATION AND COMMAND STRUCTURE

If the computer screen does not display what you are typing, go to the menu bar in Tera Term, click on Setup, select Terminal, and checkmark the “Local Echo” box.

1. All alpha characters are in UPPER CASE (turn on your Caps Lock key).

2. All transmissions from the AMM -15 to the host computer end with a Carriage Return (CR) followed by a Line Feed (LF), except for uploads, which end with just a (CR).

3. An invalid command, followed by pressing the Enter key, generates the transmission of a “?” character.

4. The data transmission format is: (TAB)##.#,(TAB)###.#(CR)(LF) where the numbers (#) correspond to Dew Point and Temperature respectively.
   Each scan of the sensors is preceded by a time stamp in the form: MM/DD/YY hh:mm:ss
   For example, 04/10/13 16:30:05 is April 10, 2013 at 4:30:05 PM.

5. The time interval between com- mands should be at least 1 second.

6. During the execution of a command, the scanning of the sensors will be suspended. This fact should be taken into consideration, mainly in connection with the uploading command.

REPLACEMENT PARTS

Inline Filter …………………………………………………………………………………. #5355
¼” OD Polypropylene Tubing (6-foot) ……………………………………. ST-AMM-15
If you need additional help for your particular application, contact Ohmic at 410-820-5111, or e-mail us at sales@ohmicinstruments.com.

AMM-15 ANALOG OUTPUT TABLE

DP             Vout (mV)| DP| Vout (mV)| DP Vout (mV)| DP                 Vout (mV)
---|---|---|---|---
-55| 0.00| -17| 253.| 21507.| 59| 760.00
-54| 7.| -16| 260.00| 22513.| 60| 767.
-531| 13.| -15| 267.| 231520.00| 61 V| 773.
-52| 20.00| -14| 273.| 24527.| 62| 780.00
-51| 27.| -13| 280.00| 25533.| 63| 787.
-50| 33.| -12| 287.| 26540.00| 64| 793.
-49I| 40.00| -11| 293.| 27| | 800.00
-48| 47.| -10| 300.00| 28553.| 66| 807.
-474| 53.| -9| 307.| 294560.00| 67 ii| 813.
-46| 60.00| -8| 313.| 30567.| 68| 820.00
-45| 67.| -7| 320.00| 31573.| 69| 827.
-44| 73.| -6| 327.| 32580.00| 70| 833.
-43| 80.00| -5| 333.| 33587.| 71| 840.00
-42| 87.| -4| 340.00| 34593.| 72| 847.
-41| 93.| -3| 347.| 35600.00| 73| 853.
-40| 100.00| -2| 353.| 36607.| 74| 860.00
-39| 107.| -1| 360.00| 37613.| 75| 867.
-38| 113.| 0| 367.| 38620.00| 76| 873.
-37| 120.00| 1| 373.| 39627.| 77| 880.00
-36| 127.| 2| 380.00| 40633.| 78| 887.
-35| 133.| 3| 387.| 41640.00| 79| 893.
-34| 140.00| 4| 393.| 42647.| 80| 900.00
-33| 147.| 5
6| 400.00
406.67| 43653.| 81
82| 906.67
913.33
-32| 153.| 44660.00
-31| 160.00| 7| 413.| 45667.| 83| 920.00
-30| 167.| 8| 420.00| 46673.| 84| 927.
-29| 173.| 9| 427.| 471680.00| 85| 933.
-28| 180.00| 10| 433.| 48687.| 86| 940.00
-271187.| 1| 440.00| 49693.| 87| 947.
-26| 193.| ’12| 447.| 50700.00| 88| 953.
-25| 200.00| 13| 453.| 5111| | 960.00
-24| 207.| 14| 460.00| 52713.| 90| 967.
-23| 213.| 15| 467.| 534720.00| 911| 973.
-22| 220.00| 16| 473.| 54727.| 92| 980.00
-21| 227.| 17| 480.00| 551733.| 93| 987.
-20| 233.| 18| 487.| 56740.00| 94| 993.
-19| 240.00| 19| 493.| 571747.| 95| 1000.00
-18| 247.| 20| 500.00| 58 753.33| _|

NOTE: Output is calibrated only in the range of –40°F to +80°F and –40°C to +27°C.

GENERAL SPECIFICATIONS

AIR-LINE MOISTURE MONITOR – Model AMM-15
ELECTRICAL
Water Vapor Sensor: HC-610 (Thin Film Polymer)
Temperature Sensor: 10K NTC Thermistor
Dewpoint Range: -40 to +80 ºF
Dewpoint Accuracy: ±4 ºF from -40 to +20; ±2 ºF from +20 to +80
Dry-Bulb Range: 0 to 140 ºF
Dry-Bulb Accuracy: ±2 ºF
Average Response Time: 10 Seconds / 63% Step
Max. Inlet Temperature: 140 ºF 550 ºF with Heat Sink Tubing
Maximum Line Pressure: 120 PSIG
Display: 3-1/2 Digit LCD, 0.5″ Character Height
Power: 4-AA Alkaline Batteries
Microprocessor: Philips 80C552
Clock Rate: 3.6864 MHz

COMMUNICATIONS
Type: RS-232C
Rate: 9600 Baud
Parity: None
Data Bits: 8
Stop Bits: 1
Flow Control: Off
Format: ASCII
Connector: DB9 Female

PHYSICAL
Housing: High Impact ABS Plastic
Size: 8.25” x 4.0” x 1.6” (LWH)
Weight: 24 Ounces

WARRANTY

Not withstanding any provision of any agreement the following warranty is exclusive.
Ohmic Instruments warrants each instrument it manufactures to be free from defects in material and workmanship under normal use and service for the period of 1-year from date of purchase. This warranty extends only to the original  purchaser. This warranty shall not apply to fuses or any product or parts which have been subjected to misuse, neglect, accident, or abnormal conditions of operation.

In the event of failure of a product covered by this warranty, Ohmic Instruments will repair and recalibrate an instrument returned within 1 year of the original purchase: provided the warrantor’s examination discloses to its satisfaction that the product was defective. The warrantor may, at its option, replace the product in lieu of repair. With regard to any instrument returned within 1 year of the originapurchase, said repairs or replacement will be madewithout charge. If the failure has been caused by misuse, neglect, accident, or abnormal conditions of operations, repairs will be billed at a nominal cost. In such case, an estimate will be submitted before work is started, if requested.

THE FOREGOING WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS, OR ADEQUACY FOR ANY PARTICULAR PURPOSE OR USE. OHMIC INSTRUMENTS SHALL  NOT BE LIABLE FOR ANY SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, WHETHER IN CONTRACT, TORT, OR OTHERWISE.

All shipments of Ohmic Instruments products should be made via United Parcel Service or “Best Way” prepaid. The instrument should be shipped in the original packing carton, or if it is not available, use any suitable container that is  rigid and of adequate size. If a substitute container is used, the instrument should be wrapped in paper and surrounded with at least four inches of excelsior or similar shock absorbing material.

CLAIM FOR DAMAGE IN SHIPMENT TO ORIGINAL PURCHASER

The instrument should be thoroughly inspected immediately upon delivery to purchaser. All material in the shipping container should be checked against the enclosed packing list. The manufacturer will not be responsible for shortages against the packing sheet unless notified immediately. If the instrument is damaged in any way, a claim should be filed with the carrier immediately. (To obtain a quotation to repair shipment damage, contact Ohmic Instruments.) Final claim and negotiations with the carrier must be completed by the customer.

Ohmic Instruments will be pleased to answer all application or use questions, which will enhance your use of this instrument. Please address your requests or correspondence to: Ohmic Instruments 3081 elm Point Industrial Drive St. Charles, MO 63301 USA ATTN: Technical Support. Or call Ohmic Technical Support at 410-820-5111.
All rights reserved. This manual may not be reproduced in full or in part without written permission of Ohmic Instruments Company. Information contained within this manual is believed to be accurate and reliable. However, Ohmic Instruments Company assumes no liability for its use. Ohmic Instruments Company reserves the right to supply its instruments with design changes and/or component substitutions that may not be documented in this manual. Contact our engineering department for information on equipment revisions not covered in this manual.

www.ohmicinstruments.com
Sales: sales@ohmicinstruments.com
Service: service@ohmicinstruments.com
Phone 410-820-5111
Toll Free(800) 626-7713
Fax 410-822-9633

References

• Ohmic Instruments Inc.

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