HYDROGEN (H2) SENSOR
(PART NUMBER 20624)
OPERATIONS MANUAL
Super Systems Inc.
7205 Edington Drive
Cincinnati, OH 45249
513-772-0060
800-666-4330
Fax: 513-772-9466
www.supersystems.com
Hydrogen (H2) Sensor Operations Manual
Super Systems Inc.
Page 2 of 17
Table of Contents
Introduction ........................................................................................................................................ 3
Features ............................................................................................................................................. 3
Specifications ..................................................................................................................................... 3
Switch Settings, Jumper Settings, and Connector Assignments .................................................... 5
Location of RS-485, DC Input, and Analog Output Terminals ...................................................... 5
Dip Switch Settings ........................................................................................................................ 5
Jumper Positions – Modbus RTU/ASCII ........................................................................................ 6
9-Pin Connector ............................................................................................................................. 7
Analog Output Jumpers ................................................................................................................. 7
Plumbing Connections ................................................................................................................... 8
Analog Output Assignments .......................................................................................................... 8
Calibrating and Configuring the Sensor using the H
Configuration Utility Software ..................... 9
2
Minimum Computer Requirements ............................................................................................... 9
Configuring Communications ........................................................................................................ 9
Overview Screen ............................................................................................................................. 9
Sensor Output Configuration ....................................................................................................... 10
Sensor Output Calibration ........................................................................................................... 10
Sensor Calibration ....................................................................................................................... 11
About ............................................................................................................................................. 12
Modifying Modbus Registers ....................................................................................................... 12
Calibrating the Sensor using Modbus Registers ........................................................................ 13
Performing a Zero Calibration ................................................................................................. 13
Performing a Span Calibration ................................................................................................ 13
Changing the 4-20mA Assignments using Modbus Registers ................................................... 13
Appendix 1: Modbus Register Map .................................................................................................. 14
Warranty ........................................................................................................................................... 16
Revision History ............................................................................................................................... 17
Hydrogen (H2) Sensor Operations Manual
Super Systems Inc.
Page 3 of 17
Introduction
This sensor is designed to accurately measure Hydrogen through thermal conductivity
technology. It is capable of providing additional computations based on the Hydrogen
measurement, and it has multiple methods of digital and analog communications capabilities.
Features
• Measures H
• Calculates NH
from 0 to 100% with 0.01% resolution
2
, DA, and KN for nitrider applications
3
• Two isolated analog outputs capable of outputting current (4-20 mA or 0-20 mA) as well as
voltage (2-10 VDC, 0-10 VDC, 1-5 VDC, or 0-5 VDC)
• One RS-232 port with Modbus RTU or a simple ASCII protocol
• One RS-485 port with Modbus RTU protocol
• Wide power supply input range (9 to 30VDC)
• Small physical size
Specifications
Hydrogen measurement
• Range: 0 to 100%
• Accuracy: ±0.01%
• Repeatability: ±0.01%
• Resolution: ±0.01%
Calculated Variables for simple nitrider applications
• %NH
0 to 100%
3
• %DA (dissociated ammonia) 0 to 100%
nitriding potential
• K
N
Analog Outputs
• Two isolated analog outputs with common supply; capable of outputting current (4-20 mA or
0-20 mA) as well as voltage (2-10 VDC, 0-10 VDC, 1-5 VDC, or 0-5 VDC)
• Output variables: %H
, %NH3, %DA, and KN on either output
2
• Adjustable range of PV: zero and span
• Resolution: 0.005 mA
• Accuracy: ±0.01% of range
• Linearity: ±0.01%
• Minimum load resistance: 0 Ohms
• Maximum load resistance: 500 Ohms
Sample flow rate
• 1.5 to 2 cfh
RS-232 Serial Communications
• Protocols: Modbus RTU or a simple ASCII
• Baud rates: 9600, 19200, or 38400
• Format: 8 bits No parity, 1 stop bit, No handshaking
• Connection: DB-9F
Hydrogen (H2) Sensor Operations Manual
Super Systems Inc.
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RS-485 Serial Communications:
• Protocol: Modbus RTU
• Baud rates: 9600, 19200, or 38400.
• Format: 8 bits No parity, 1 stop bit, No handshaking
Power requirement
• 9 to 30 volts DC @ 2 watts
Temperature and Humidity
• Electronics Operating: 0 to 50 °C, RH 0 to 90% non-condensing
• Sample gas: 0 to 70 °C, RH 0 to 90% non-condensing
• Storage: -20 to 70 °C, RH 0 to 90% non-condensing
Dimensions:
See Figure 1.
Weight:
Material:
Figure 1 - H2 Sensor Dimensions
350 g
Stainless steel sensor housing
Hydrogen (H2) Sensor Operations Manual
Super Systems Inc.
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Wiring:
See Figure 2.
Figure 2 - H2 Sensor Wiring
Switch Settings, Jumper Settings, and Connector Assignments
Location of RS-485, DC Input, and Analog Output Terminals
(Items “A” and “B” in Figure 2)
There are two terminal blocks on the H2 cell circuit board. Figure 2 shows their locations.
One block (“A”) contains the analog output terminals. Jumper settings on the circuit board are
used to change whether resistance or voltage is generated. These jumper settings can be found
in “Analog Output Jumpers” below.
Another block (“B”) contains the digital communications (RS-485) and power (DC) terminals.
Dip Switch Settings
(Item “C” in Figure 2)
The first three dip switches determine the Modbus address. The address can be set for any
number between 1 and 8 using a binary numbering system where Bit #1 is the least significant
bit and Bit #3 is the most significant bit. The diagram below describes the switch position for
each possible address. The shaded area indicates the location of the switch.
Hydrogen (H2) Sensor Operations Manual
Super Systems Inc.
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ADDRESS 1
ADDRESS 2
ADDRESS 3
ADDRESS 4
1 O 1 O 1 O 1 O
2 N 2 N 2 N 2 N 3 3 3 3
4 4 4 4 ADDRESS 5
ADDRESS 6
ADDRESS 7
ADDRESS 8
1 O 1 O 1 O 1 O 2 N 2 N 2 N 2
N
3 3 3 3 4 4 4 4
Protocol
1 O 1 O
2 N 2 N
3 3 4 4
1 2 3
4
1 2 3
4
Figure 3 - Dip Switch Settings (#1, #2, #3)
The last dip switch (#4) indicates the communication protocol. The ‘Off’ position is Modbus RTU
mode, and the ‘On’ position emulates the simple ASCII protocol of the previous version of the
SSI Hydrogen Sensor. The diagram below describes the switch position for each protocol. The
shaded area indicates the location of the switch.
Modbus RTU
Protocol
Previous SSI
Sensor
Figure 4 - Dip Switch Positions (#4)
Jumper Positions – Modbus RTU/ASCII
(Item “D” in Figure 2)
Four jumper terminals can be found on the board approximately 1.5” (3.81cm) to the left of the
RS-485 connections (specifically, when looking at the board in the orientation shown in Figure
2). These jumpers determine the pins that transmit and receive data via RS-232 communication.
The jumpers should be on Pins 2 and 3 for normal Modbus RTU operation (pin 2 is receiving and
pin 3 is transmitting). The jumpers should be on Pins 1 and 4 if the sensor is being used to
communicate via the simple ASCII protocol used on the previous version of the SSI Hydrogen
Sensor (pin 2 is transmitting and pin 3 is receiving).
Modbus RTU Protocol
Simple ASCII Protocol
Figure 5 - Jumper Positions (Modbus RTU/ASCII)