MS1-SCAN Protocol Converter User Manual Instrumental Solutions
Contents
1. MS1 SCAN Protocol Converter User Manual LPT Lt AD EIR NEL be me 51 2150 fk ModBus SDI 12 Protocol Converter SDI 12 ModBus ISI Instrumental Solutions Inc WWW ISIDEV NET Introduction The MS1 SCAN protocol converter can take readings from 1 or more ModBus registers on a single ModBus instrument using an RS232 or RS485 interface and make that data available on a SDI12 network It is preconfigured to read the device status register and the first seven parameter data registers on the S CAN spectrometer probes For special situations the unit can be reconfigured via the text based user interface using most any terminal software Getting Started All wiring connections are made inside the weatherproof enclosure with the wires passing through the waterproof fitting on the rear panel of the enclosure Remove the rear panel by removing the 4 retaining screws and slide the circuit board out to gain access to the connectors see Figure 1 The DB9P connector labeled RS 232 is used for connecting to RS 232 devices as well as for configuring the protocol converter via the text based user interface Permanent installations using the RS 232 interface should use screw terminals 4 6 labeled GND 232 TX and 232 RX respectively SDI12 and RS 485 connections are made on terminals I amp 2 and 7 amp 8 respectively When connecting the S CAN probe to the converter the A terminal o2. These operations are what get each data field from the S CAN probe making it available via SDI12 The remaining operations 4 8 are not enabled by default but they are preconfigured to read parameters 3 7 in the S CAN probe They can be enabled or modified as required 14 Restore default settings This selection resets all configuration parameters to the factory default settings 15 Resume normal operation This selection exits configuration mode and returns the converter to online operation Configuration mode has an inactivity timeout of 1 minute if at any time after entering configuration mode no characters are typed for 1 minute the converter will automatically return to normal online operation If this occurs in the middle of configuring a Modbus operation no changes will be made to the configuration Modbus operation changes are not saved until the user has stepped through all of the settings for the operation Copyright 2010 Instrumental Solutions Inc All Rights Reserved Specifications SDI 12 interface Modbus interface Text interface Operating system Indicators Connections Temperature range Power requirements Enclosure External dimensions Weight SDI 12 v1 3 compliant Modbus ASCII 9600 baud 8 bit no parity 9600 baud 8 bit no parity no handshake Instrumental Solutions ISOS 11 2 bicolor LEDs for transmit receive indication Internal screw terminals DB9 male DTE 40 C t
3. ameter 1 Parameter 2 To change a configuration setting type the number of the setting followed by the Enter key The configuration mode has an inactivity timeout of 1 minute If at any point during configuration the user goes 1 minute without typing anything the converter automatically returns to normal online operation Setting changes are saved as they are entered so any changes completed during the configuration session will not be lost if a inactivity timeout occurs The following section describes each setting in detail 1 SDI12 address This is the address that the MS1 SCAN will answer to on the SDI12 network The default value is 0 This value must match the address that the SDI12 master uses when attempting to communicate with the MS1 SCAN If the SDI12 master has the ability to scan the network for sensors this is the address that will be associated with MS1 SCAN on the SDI12 master 2 SDI12 data ready time This is the maximum length of time in seconds that the Modbus device should take to have data available after a measurement request The default value is 60 The MS1 SCAN reports this value back to the SDI12 master in response to a measurement request The SDI12 master must wait this length of time before requesting data from the MS1 SCAN However if the SDI12 master issues a non concurrent measurement request recommended the MS1 SCAN will issue a Service Request to the SDI12 master as soon as data is available from th
4. d to pin 7 for flow control loopback Pin 9 No connection Table 2 Terminal Connections 1 SDI12 data line 2 SDI12 ground 3 12VDC input 4 Ground 5 Transmit data RS232 output 6 Receive data RS232 input 7 RS485 line A 8 RS485 line B Table 3 Jumper J6 Jumper installed on I amp 2 Enable RS 232 operation Jumper installed on 2 amp 3 Enable RS 485 operation Default Configuration To view the current configuration or configure the MS1 SCAN it is first necessary to move the jumper on header J6 which is located immediately behind the screw terminal block from its normal 2 3 position to position 1 2 This jumper must be returned to position 2 3 for the ModBus interface to work Please refer to Table 3 above and the highlighted portion in Figure 1 where the jumper is shown in position 2 3 O Copyright 2010 Instrumental Solutions Inc All Rights Reserved Next plug one end of a null modem cable into the DB9P connector on the converter and the other end into an available serial port on a PC Terminal software should be set for 9600 baud 8 data bits no parity and no flow control To enter configuration mode quickly type 3 question mark characters The MS1 SCAN should respond with the following screen amp serial Hyper Terminal File Edit Yiew Call Transfer Help DS H ISI MS1 CAN Modbus SDI12 Converter Firm
5. e Modbus device This causes the SDI12 master to immediately issue a data retrieval request even if the data ready time has not been reached This can significantly speed up the data retrieval cycle For more information concerning the SDI12 protocol see http www sdi 12 org Copyright 2010 Instrumental Solutions Inc All Rights Reserved 3 Modbus address This is the address that the MS1 SCAN will send Modbus requests to on the RS232 and RS 485 interface The default value is 4 which matches the default address of the S CAN probe 4 Modbus mode This sets the Modbus operating mode The choices are ASCII and RTU Modbus RTU is the default which matches the default setting of the S CAN probe 5 Modbus read function This sets the function code that will be sent to the Modbus device to read the data registers on the Modbus device This must be set to 4 for the S CAN probe 6 Modbus operations 1 8 Upon receiving a measurement request from the SDI12 master the MS1 SCAN executes a series of Modbus operations as defined by these settings An operation can be 1 of 3 types a Read type which reads a Modbus register on the attached sensor a Write type which writes a Modbus register on the attached sensor or a Test type which repeatedly reads a Modbus register on the attached sensor until the value read matches a test value specified in the operation For example before reading the data registers on the S CAN
6. his case register number 121 in the S CAN probe has a data type of bitmask which translates just fine to a 16 bit unsigned integer Press the ENTER key to accept the setting and take you to the next step Number of registers Current setting 1 New setting Enter a new value for the number of Modbus registers that this operation is to operate on or hit Enter with no entry to keep the current setting In this case we want to operate on a single register Type of operation Test Spacebar to change Enter to accept The spacebar steps through the available types for this operation In this case we want to Test to the specified register on the S CAN probe Operation data Current setting 0 New setting Enter the data value to compare the probe value to which in this case will be 0 This means that the MS1 SCAN will continuously read the probe until the returned value is equal to 0 or until it times out waiting for the probe to return 0 The timeout value is approximately 2 minutes Copyright 2010 Instrumental Solutions Inc All Rights Reserved Operation name Current setting Test device status 0 New setting This is a free form text description of what the operation does Hit Enter with no entry to keep the current setting After the Test operation finishes whether due to the test condition becoming true or a timeout occurring the converter continues with Operations 2 3 which are Read type operations
7. n the probe should connect to the RS 485 A terminal on the converter and the B terminal on the probe should connect to the RS 485 B terminal on the converter See Tables I amp 2 for more information on making electrical connections When configuring the MS1 SCAN a null modem serial cable included and terminal program such as Hyperterm is required When configuring the MS1 SCAN any other RS 232 devices must be disconnected from the converter The MS1 SCAN is preconfigured to operate with the S CAN spectrometer probe and configuration is not normally required The converter has 2 multi color LED indicators on the front panel for indicating SDI12 and Modbus data activity The indicators light up green when the converter is receiving data on the associated interface and red when the converter is sending data on the interface These can be used to help diagnose communication problems Copyright 2010 Instrumental Solutions Inc All Rights Reserved Figure 1 O Copyright 2010 Instrumental Solutions Inc All Rights Reserved Table 1 DB9P Connections Pin I No connection Pin 2 Receive data RS232 input Pin 3 Transmit data RS232 output Pin 4 DTR internally tied to pin 6 for flow control loopback Pin 5 Signal ground Pin 6 DSR internally tied to pin 4 for flow control loopback Pin 7 RTS internally tied to pin 8 for flow control loopback Pin 8 CTS internally tie
8. o 85 C 12VDC 35ma idle 35 ma avg 55ma max Extruded aluminum IP65 rated 7 52 19 1cm L 3 48 8 84cm W 1 85 4 7cm H 15 ounces Copyright 2010 Instrumental Solutions Inc All Rights Reserved
9. probe it s a good idea to read the device status held in input register 121 and wait until it returns a value of 0 Operation 1 accomplishes this 6 Modbus operation 1 T Test device status 0 The indicates that this particular operation is enabled A disabled operation appears as The T indicates that this is a Test operation Test device status 0 is a free form text description of what the operation does To view or modify the details of a Modbus operation type its menu selection number and hit Enter For example to view modify operation 1 menu selection 6 type 6 and hit Enter You will be led through the following dialog Copyright 2010 Instrumental Solutions Inc All Rights Reserved 6 Modbus operation 1 Enabled Yes Spacebar to change Enter to accept The spacebar will toggle this setting between Yes and No Press the ENTER key to accept the setting and take you to the next step Modbus register Current setting 121 New setting Enter a new value for the Modbus register or hit Enter with no entry to keep the current setting In this case we are operating on register 121 which is the device status register in the S CAN probe Data type 16 bit unsigned integer Spacebar to change Enter to accept The spacebar steps through all of the data types supported by the MS1 SCAN This setting must agree with the data type of the Modbus register being referenced In t
10. ware v1 2 ISOS 11 kernel v2 0 Copyright 2010 Instrumental Solutions Inc SDI12 address H SDI12 data ready time 60 Modbus address Modbus mode Modbus read function Modbus operation 1 device status H Modbus operation 2 parml value Modbus operation 3 parm2 value Modbus operation 4 parm3 value Modbus operation 5 parm value Modbus operation 6 parmd value Modbus operation parm6 value Modbus operation parm value Restore default setting Resume normal operation Disconnected 9600 8 N 1 NOTE If the converter fails to respond try again typing as quickly as you can If still no response remove and re apply power to the converter while watching the front panel LEDs Both LEDs should immediately light up red then turn green after about half a second then go out after another half second If this doesn t happen check the power wiring for proper voltage and polarity The MS1 SCAN operates on 9 14 volts DC If the LEDs don t light when power is applied there is a problem with the converter If the LEDs light but there is still no response after typing question marks make sure that you are using a null modem serial cable which crosses pins 2 amp 3 between ends If the unit fails to respond there may be a problem with the converter Copyright 2010 Instrumental Solutions Inc All Rights Reserved The default configuration returns fields to the SDI12 master in the following order Par
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