2100-A16 Modbus RTU Registers:
1. The multiplexers 1-4 cannot be used if the stations Analogue outs AO1 & AO2 are used for general purpose outputs or retransmission controls.
2. Analogue Inputs 1-16 scaling
0-FFF = 0-4095, which is ranged according to the range selected for each input.
For RTD -25 to +25 , then 0 =-25, 4095=+25,
For RTD 0 to +25 , then 0 =0, 4095=+25,
For DCXX range =0 to 100 %, 0=0 %, 4095= 100 %.
3: Counter Inputs
Value ranges from 0-FFFF which is 0 – 65535. Max speed 50 Hz. Count value is reset to zero on power up.
4: Analogue Outputs.
Mode is set in Station programming dialog box, Advanced, AO1 & AO2 mode.
Mode 1 is Multiplexer output (AO1, AO2 drive 2100-M only)
Mode 2 is SCADA outputs, AO1,AO2 can be set via protocol.
Mode 3 is retransmission of input to AO1, clock and reset channel selection
Mode 4 is retransmission of input to AO1, binary channel selection
If AO1 and AO2 are used for driving 2100-M units, do not write the analogue out value using the RTU messages as it will interfere with the 2100-M driver.
5: Analogue Input Speed.
Inputs are scanned sequentially by the A16, a read of the data locations, reads the last value read and does not force the A16 to read the inputs requested by the protocol read. The normal read speed with all sixteen inputs is 4 channels/second. Channels that are not scanned can be disabled via the station programming dialog boxes. To speed up operation for multiplexer mode, set the Scan Mode on the advanced dialog box to Multiplexer Priority.
2100-A16 Modbus Details:
Modbus RTU Only
8 Bits, No Parity (Fixed)
9600,4800,2400 Link selectable.
Error Check standard Modbus CRC.
End of message framing delay = min 5 mSec, max 7.5 mSec. (Minimum spec is 3.5 mSec at 9600 baud). Counting is based on internal 2.5 mSec timer.
Station addresses 0-64. The station number is programmed via the Program Address dialog box, which ties a station number to the serial number of the station which the Modbus protocol then uses. The Factory set default station number for all stations is station #1. Station 0, broadcast commands are not supported.
Station address and input range configuration etc are set using the MicroScan Station Programming software.
Setup of onboard station controllers and other station parameters supported in eeprom are also set via the programming dialog boxes.
These parameters are not accessible via the protocol.
The station can be tested with the Stations test dialog box which shows the current values of the inputs and relay states, analogue output values can be set.
16 analogue inputs, 16 bit ADC, RTD, TC, DC internal scaling by A16 unit. Nominal 48,000 to 60,000 steps depending on range selected.
2 Digital outputs
4 Digital inputs
2 Analogue outputs,12 Bit
Optional – 16 extra digital outputs 2100-R2
Optional – 4 times 2100-M 16 analogue input expander (uses AO1 & AO2 for clock and reset).
2100-ME Memory Board cannot be used when Modbus RTU protocol is used.
Using the Modbus Protocol:
Use the station programming dialog boxes to set the address of the unit and the ranges of inputs etc. Then power down unit, insert link in position S1-6 and power up unit. It is then ready for Modbus RTU use. RTU mode is not recognized unless a power up occurs with S1-6 link in.
To use again via programming dialog boxes, power down the unit, remove link S1-6, and power the unit back up.
Note the station will not recognize programming message when the S1-6 link is on.
Standard protocol, Omron PLC Message Modbus RTU protocol only
If using Modbus RS485, put Comms links in 485 mode, ie L3 and L4 links in.
The retransmission modes of AO1, AO2 can be used when the Modbus RTU protocol is used.
Supported Modbus Command
Maximum length of Modbus command = 32 bytes. Maximum length of Modbus reply = 80 bytes.
The 2100-A16 was set tested with Sytech set to the following:
Modicon 984 PLC
Serial Modbus binary protocol.
Concerning the 2100-A16, make sure link 6 is fitted as per the instructions above.
Note: This information applies to the 2100-A16 ONLY.
The 2400-A16 will auto-detect Modbus operation.
Note: For programming the 2100-A16, leave in MicroScan ASCII mode (factory default). Once all channels etc are programmed, follow the steps below to change to Modbus mode.
Configure the 2100-A16 (Rev 1.3) for Modbus RTU mode:
1. Power down the 2100-A16
2. Place a jumper on S1-6
(Note: To configure the 2100-A16-NET for Modbus TCP mode, place the jumper in S1-5)
3. Power up the 2100-A16